- NANOG - lists.nanog.org

URL mixup
by Susan R. Harris 29 Nov '95

29 Nov '95

My apologies for mixing up the URLs in this afternoon's "new RA tools" message. The tools for generating NAP routing table and route flap reports are both available at: http://www.ra.net/~ra/statistics/ --Susan Harris

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Re: outages, quality monitoring, trouble tickets, etc
by Sean Donelan 28 Nov '95

28 Nov '95

>From: kwe(a)6SigmaNets.COM (Kent W. England) >I'm skeptical of any end-to-end availability figures over 97%. I don't >think they reflect the reality of leased line circuits today, or else they >don't include the leaf node circuits and only report backbone availability. >For a highly redundant backbone, almost any definition of availability >should result in a number like 99.mumble%. Remember 99.9% availability >means less than 9 hours outage per year. Routing hiccups take that much. >One or two leased lines outages is all you get for 9 hours. The real world >is a lot less available than that. Thank you! I thought I was living in a twilight zone with people reporting 99.9% network availability. This is the rathole end-to-end network useablity. The customer is interested in end-to-end useability. While the network operator can only easily measure intra-network modules. I can't tell you the answer, but there is definitely something happening with customer perceptions of Internet useability. Looking at the numbers I would agree a single leased circuit should be less reliable (single point of failure) than a highly redundant backbone. But by our customer perceptions, that isn't the case. Either we have better than "normal" leased circuits, or the highly redundant backbones aren't, or our customers needs are based something we aren't directly measuring. Highly redundant backbones remain extremely vunerable to the "glitch." Human glitches, software glitches, "impossible" data glitches. Redundant backbones do protect against the backhoe "glitch." >But since half the web servers I try to talk to refuse me half the time, >I'm not sure that network availability per se (HWB's complaints duly >acknowledged) is the tallest pole in the tent. Part of this problem is the growing number of interdepencies (complexity, chaos?). Even if each individual module is working 99.9% of the time, the probabilities start looking pretty bad when all need to be working at the same time. To make a web connection, you have a string of name servers, a string of networks to the name servers, a string of routers on those networks, another string of networks to the web server, another string of routers, more strings of networks and routers and servers on the return path. I'm amazed it even works 50% of the time. Unfortunately our customers aren't always as understanding. Since error reporting sucks in most network applications, it becomes the fault of whatever help desk happens to take the customers phone call. -- Sean Donelan, Data Research Associates, Inc, St. Louis, MO Affiliation given for identification not representation

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Re: CIDR FAQ
by Steven J. Richardson 28 Nov '95

28 Nov '95

Hank: I'd really appreciate just getting this much message. Thanks, Steve R./Merit > Date: Tue, 28 Nov 95 13:11:21 IST > From: Hank Nussbacher <HANK(a)taunivm.tau.ac.il> > To: cidrd(a)IEPG.ORG, nanog(a)merit.edu, inet-access(a)earth.com, iap(a)vma.cc.nd.edu, local-ir(a)vma.cc.nd.edu, local-ir(a)apnic.net > > ------------------------------------------------------------------------ > The CIDR FAQ > Version 5 > 15 November 1995 > ------------------------------------------------------------------------ > The following document is a collection of Frequently Asked Questions > about CIDR. This document is not meant to be a networking/routing > guide and tutorial. Where appropriate pointers to other documents > of a more general nature have been mentioned. > > Updates from a previous version are marked with a '|' in column 1. > > If you have any questions you would like added, please send them to > the editor mentioned below: > > Hank Nussbacher (Tel Aviv University and IBM Israel) > hank(a)vm.tau.ac.il or hank(a)ibm.net.il > > If you would like to "discuss" items from this FAQ please send > your mail to cidrd(a)iepg.org > > This FAQ is being distributed to the following groups and lists: > alt.internet.services > alt.internet.access.wanted > nanog(a)merit.edu > inet-access(a)earth.com > iap(a)vma.cc.nd.edu > local-ir(a)ripe.net > cidrd(a)iepg.org > |local-ir(a)apnic.net > > To retrieve the most up-to-date version of this document: > |- ftp://ftp.ibm.net.il/pub/docs/cidr.faq > |- http://www.rain.net/faq/cidr.faq.html > ------------------------------------------------------------------------

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Re: outages, quality monitoring, trouble tickets, etc
by Jonathan Heiliger 28 Nov '95

28 Nov '95

On Nov 27, 9:17am, Sean Doran wrote: > Jonathan> Everyone likes to portray > Jonathan> the image of having a 99.98% uptime whenever > Jonathan> possible, even though most folks realize > Jonathan> that it just plain isn't possible > > Well, more importantly, what on earth does a number like > that mean? Sorry, bad choice of words. Rather than uptime, availability would be the proper word. Availability tends to be the amount of time the network is "available" for the customer to receive their expected service (whether guaranteed in writing or not), and for the customers expectation of how the service will perform when it is considered "in-service" is met. -jh-

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New tools from the RA project (fwd)
by Elise Gerich 28 Nov '95

28 Nov '95

FYI....just in case you all aren't on these other lists. --Elise >Susan R. Harris writes: > From owner-cidrd(a)aarnet.edu.au Tue Nov 28 17:01:20 1995 > Date: Tue, 28 Nov 1995 16:47:35 -0500 (EST) > From: "Susan R. Harris" <srh(a)merit.edu> > To: cidrd(a)iepg.org, bgp(a)ans.net > Subject: New tools from the RA project > Message-ID: <Pine.SUN.3.91.951128164516.1874K-100000(a)home.merit.edu> > MIME-Version: 1.0 > Content-Type: TEXT/PLAIN; charset=US-ASCII > > Greetings - Just a quick note to let you know about some new tools > available from the Routing Arbiter project. Comments and bug reports > welcome; please send 'em to ra-team(a)ra.net. > > > A new RADB tool tells you which RADB routes in an AS are duplicated or > covered by less specific routes in the IRR: > > http://www.ra.net/~ra/RADB.tools.docs/.reports.html > > > A new tool to generate Internet routing table reports for each NAP > tells you (1) the maximum number of announced routes in the Route > Server's routing tables, (2) the complete Internet routing table, > listed by prefix and associated AS path, as seen by the NAP's Route > Servers, or (3) the number of routes seen by each Route Server, listed > by RS peer and origin AS. > > The reports in (2) from the Washington, D.C. NAP (MAE-East) have shown > some interesting numbers, like 32-bit host announcements and prefixes > reserved by RFC 1597 (private internet address allocation). > > > You can now generate NAP route flap reports by RS peer as well as by > AS origin, prefix, and specific AS: > > http://www.ra.net/~ra/statistics/.routes.html > ------------------------------------------------------------------------ > Susan R. Harris, Ph.D. Merit Network, Inc. srh(a)merit.edu > Phone: (313) 936-2100 Fax: (313) 747-3185 > ------------------------------------------------------------------------ > > > >

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New tools from the RA project
by Susan R. Harris 28 Nov '95

28 Nov '95

Greetings - Just a quick note to let you know about some new tools available from the Routing Arbiter project. Comments and bug reports welcome; please send 'em to ra-team(a)ra.net. > A new RADB tool tells you which RADB routes in an AS are duplicated or covered by less specific routes in the IRR: http://www.ra.net/~ra/RADB.tools.docs/.reports.html > A new tool to generate Internet routing table reports for each NAP tells you (1) the maximum number of announced routes in the Route Server's routing tables, (2) the complete Internet routing table, listed by prefix and associated AS path, as seen by the NAP's Route Servers, or (3) the number of routes seen by each Route Server, listed by RS peer and origin AS. The reports in (2) from the Washington, D.C. NAP (MAE-East) have shown some interesting numbers, like 32-bit host announcements and prefixes reserved by RFC 1597 (private internet address allocation). > You can now generate NAP route flap reports by RS peer as well as by AS origin, prefix, and specific AS: http://www.ra.net/~ra/statistics/.routes.html ------------------------------------------------------------------------ Susan R. Harris, Ph.D. Merit Network, Inc. srh(a)merit.edu Phone: (313) 936-2100 Fax: (313) 747-3185 ------------------------------------------------------------------------

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Re: outages, quality monitoring, trouble tickets, etc
by Sean Doran 28 Nov '95

28 Nov '95

>"it's AOL's fault" because the provider themselves didn't properly >set up an RADB entry so the ANS network ... I find it amusing that the only utility ascribed to the RADB by network operators almost always has to do with being reachable from ANS. It's also tragic, actually. I'm glad that my taxes go up to the receiver-general for Canada sometimes rather than going to a project which frequently appears to benefit one and only one U.S.-based network service provider. Anyway, typically the only time we hear problems with respect to the RADB is when someone wants to talk to AOL and cannot, or when some ANS customer can't get to anything behind us or somewhere downstream from us. It'd be very interesting to see what happens to the RADB the second AOL has Internet connectivity through another provider... It'd certainly reduce the incidence of people updating the RADB to fix disconnectivities. Sean.

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CERT Summary CS-95:03
by CERT Advisory 28 Nov '95

28 Nov '95

--------------------------------------------------------------------------- CERT Summary CS-95:03 November 28, 1995 The CERT Coordination Center periodically issues the CERT Summary to draw attention to the types of attacks currently being reported to our incident response staff. The summary includes pointers to sources of information for dealing with the problems. We also list new or updated files that are available for anonymous FTP from ftp://info.cert.org Past CERT Summaries are available from ftp://info.cert.org/pub/cert_summaries --------------------------------------------------------------------------- Recent Activity --------------- Since the September CERT Summary, we have seen these continuing trends in incidents reported to us. The majority of reported incidents fit into four categories: 1. Packet Sniffers We continue to see daily incident reports about intruders who have installed sniffers on compromised systems. These sniffers, used to collect account names and passwords, are frequently installed with a kit that includes Trojan horse binaries. The Trojan horse binaries hide the sniffer activity on the systems on which they are installed. For further information and methods for detecting packet sniffers and Trojan horses, see the following files: ftp://info.cert.org/pub/cert_advisories/CA-94:01.network.monitoring.attacks ftp://info.cert.org/pub/cert_advisories/CA-94:01.README ftp://info.cert.org/pub/cert_advisories/CA-94:05.MD5.checksum ftp://info.cert.org/pub/cert_advisories/CA-94:05.README 2. Exploitation of SGI lp Vulnerability The vulnerability described in CERT advisory, CA:95:15 "SGI lp Vulnerability" continues to be exploited, though we have seen a decline in the number of reports since the advisory was released on November 8. Intruders gain unauthorized access to Silicon Graphics, Inc. (SGI) IRIX systems through a passwordless lp account; they use this initial access to leverage additional privileges on the compromised system. As distributed by SGI, the lp account (as well as other accounts), has no password on a newly installed system. This fact is addressed in the documentation that SGI distributes with their systems: "IRIX Advanced Site and Server Administrative Guide" (see the chapter on System Security). More information on this vulnerability and how it can be addressed can be obtained from ftp://info.cert.org/pub/cert_advisories/CA-95:15.SGI.lp.vul 3. Network Scanning We continue to receive several reports each week of intruders using the Internet Security Scanner (ISS) to scan both individual hosts and large IP address ranges. The ISS tool, which is described in CERT advisory CA-93:14 "Internet Security Scanner", interrogates all computers within a specified IP address range, determining the security posture of each with respect to several common system vulnerabilities. Intruders use the information gathered from such scans to gain unauthorized access to the scanned sites. As part of a defensive strategy, you may want to consider running ISS against your own site (in accordance with your organization's policies and procedures) to identify any possible system weaknesses or vulnerabilities, taking steps to implement security fixes that may be necessary. ISS is available from ftp://info.cert.org/pub/tools/iss/iss13.tar More information about the ISS tool and steps for protecting your site are outlined in the following documents: ftp://info.cert.org/pub/cert_advisories/CA-93:14.Internet.Security.Scanner ftp://info.cert.org/pub/cert_advisories/CA-93:14.README ftp://info.cert.org/pub/tech_tips/security_info ftp://info.cert.org/pub/tech_tips/packet_filtering 4. Sendmail Attacks New reports of intruders attacking sites through sendmail vulnerabilities are continuing to arrive daily, although most reports indicate the attacks have failed. The types of attacks are varied, but most are aimed at gaining privileged access to the victim machine. We encourage sites to combat these threats by taking the appropriate steps, described in the following documents: ftp://info.cert.org/pub/cert_advisories/CA-95:05.sendmail.vulnerabilities ftp://info.cert.org/pub/cert_advisories/CA-95:05.README ftp://info.cert.org/pub/cert_advisories/CA-95:08.sendmail.v.5.vulnerability ftp://info.cert.org/pub/cert_advisories/CA-95:08.README ftp://info.cert.org/pub/cert_advisories/CA-95:11.sun.sendmail-oR.vul ftp://info.cert.org/pub/cert_advisories/CA-95:11.README What's New in the CERT FTP Archive ---------------------------------- We have made the following changes since the last CERT Summary (September 26, 1995). * New Additions ftp://info.cert.org/pub/cert_advisories/ CA-95:12.sun.loadmodule.vul CA-95:13.syslog.vul CA-95:14.Telnetd_Environment_Vulnerability CA-95:15.SGI.lp.vul ftp://info.cert.org/pub/cert_bulletins/ VB-95:07.abell (lsof) VB-95-08.X_Authentication_Vul ftp://info.cert.org/pub/tools/sendmail sendmail/sendmail.8.7.1.tar sendmail/sendmail.8.7.1.tar.Z * Updated Files ftp://info.cert.org/pub/cert_advisories/ CA-93:16a.README (sendmail - note to use smrsh with all versions) CA-95:05.README (sendmail - date of Digital Equipment's patch) CA-95:08.README (sendmail - note to use smrsh with all versions) CA-95:10.README (ghostscript - patches and explanations) CA-95:13.README (syslog - information from vendors) CA-95:14.README (telnetd - information from vendors; correction to compilation example) ftp://info.cert.org/pub/tools/cops README (more recent email address for COPS author Dan Farmer) --------------------------------------------------------------------------- How to Contact the CERT Coordination Center Email cert(a)cert.org Phone +1 412-268-7090 (24-hour hotline) CERT personnel answer 8:30-5:00 p.m. EST (GMT-5)/EDT(GMT-4), and are on call for emergencies during other hours. Fax +1 412-268-6989 Postal address CERT Coordination Center Software Engineering Institute Carnegie Mellon University Pittsburgh PA 15213-3890 To be added to our mailing list for CERT advisories and bulletins, send your email address to cert-advisory-request(a)cert.org CERT advisories and bulletins are posted on the USENET news group comp.security.announce If you wish to send sensitive incident or vulnerability information to CERT staff by electronic mail, we strongly advise that the email be encrypted. We can support a shared DES key, PGP, or PEM (contact CERT staff for details). Location of CERT PGP key ftp://info.cert.org/pub/CERT.PGP_key --------------------------------------------------------------------------- Copyright 1995 Carnegie Mellon University This material may be reproduced and distributed without permission provided it is used for noncommercial purposes and credit is given to the CERT Coordination Center. CERT is a service mark of Carnegie Mellon University.

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CIDR FAQ
by Hank Nussbacher 28 Nov '95

28 Nov '95

------------------------------------------------------------------------ The CIDR FAQ Version 5 15 November 1995 ------------------------------------------------------------------------ The following document is a collection of Frequently Asked Questions about CIDR. This document is not meant to be a networking/routing guide and tutorial. Where appropriate pointers to other documents of a more general nature have been mentioned. Updates from a previous version are marked with a '|' in column 1. If you have any questions you would like added, please send them to the editor mentioned below: Hank Nussbacher (Tel Aviv University and IBM Israel) hank(a)vm.tau.ac.il or hank(a)ibm.net.il If you would like to "discuss" items from this FAQ please send your mail to cidrd(a)iepg.org This FAQ is being distributed to the following groups and lists: alt.internet.services alt.internet.access.wanted nanog(a)merit.edu inet-access(a)earth.com iap(a)vma.cc.nd.edu local-ir(a)ripe.net cidrd(a)iepg.org |local-ir(a)apnic.net To retrieve the most up-to-date version of this document: |- ftp://ftp.ibm.net.il/pub/docs/cidr.faq |- http://www.rain.net/faq/cidr.faq.html ------------------------------------------------------------------------ General questions ----------------- 1. What does CIDR stand for? CIDR stands for Classless Inter-Domain Routing and is documented in RFC1517/1518/1519/1520. CIDR is an effective method to stem the tide of IP address allocation as well as routing table overflow. Without CIDR having been implemented in 1994 & 1995, the Internet would not be functioning today. Basically, CIDR eliminates the concept of class A, B, and C networks and replaces this with a generalized "IP prefix". CIDR can be used to perform route aggregation in which a single route can cover the address space of several "old-style" network numbers and thus replace a lot of old routes. This lessens the local administrative burden of updating external routing, saves routing table space in all backbone routers and reduces route flapping (rapid changes in routes), and thus CPU load, in all backbone routers. CIDR will also allow delegation of pieces of what use d to be called "network numbers" to customers, and therefore make it possible to utilize the available address space more efficiently. See question #6 below for details on "IP prefix"s. 2. What is an ASN? ASN stands for Autonomous System Number and acts to merge many networks into a logical domain. 3. What is BGP? BGP stands for Border Gateway Protocol and is the de-facto standard for routing between Autonomous Systems in the Internet. All communications between Internet Service Providers (ISP) is handled via BGP4 which supports CIDR. 4. Why should I make the effort and convert my routing to be CIDRized? The routing tables in the Internet have been growing as fast as the Internet and the router technology specifically and computer technology in general has not been able to keep pace. In December 1990 there were 2190 routes and 2 years later there were over 8500 routes. In July 1995 there are now over 29,000 routes, which require approximately 10 MB in a router with a single peer. Routers at interconnection points (or multi-homed hosts doing full routing with many peers) receive these routes from several peers, and need several dozen megabytes of RAM (and the appropriate CPU horsepower) to handle this. A list of those routers that can handle this appears at the end of this question. Routers with 64MB of memory have the capacity for approximately 60,000 routes after which some routes will just have to be left out of the global routing tables, and the more likely ones to be left out are routes covering small pieces of address space. Without the CIDRization work that has gone on for the past 2 years the routing tables would be in excess of 65,000 routes. By CIDRizing you help the Internet reduce the routing overload as well as increasing the liklihood that in the future your routes will be carried by all ISPs. The major benefit of CIDR is to allow for continuous, uninterrupted growth of the Internet. For a significant percentage of sites connected to the Internet the value of the Internet increases with the total number of sites connected to the Internet. Therefore, taking steps needed to allow for continuous uninterrupted growth (like CIDRizing, or renumbering) is beneficial to such sites. The routers today that are available to handle the full routing table are: cisco 7000 w/ 64Mb cisco 4500 w/ 32Mb IBM ENSS and CNSS w/ 64Mb BayNetworks models AN/ASN/BLN/BCN w/ 32Mb 5. Can you give an example of a simple CIDR configuration for a cisco router? The following example creates 2 aggregates and suppresses any more specific addresses that may be contained within those aggregates. The access-list causes only those nets to be distributed as listed, and not any others that may exist in the BGP routing tables. router bgp 64100 no synchronization aggregate-address 172.16.0.0 255.248.0.0 summary-only aggregate-address 192.168.50.0 255.255.255.0 summary-only neighbor 192.168.54.2 remote-as 65000 neighbor 192.168.54.2 distribute-list 12 out default-metric 70 ! access-list 12 permit 192.168.50.0 0.0.0.255 access-list 12 permit 172.16.0.0 0.7.255.255 | Another method might be: | | router bgp 64100 | no synchronization | aggregate-address 172.16.0.0 255.248.0.0 | aggregate-address 192.168.50.0 255.255.255.0 | neighbor 192.168.54.2 remote-as 65000 | neighbor 192.168.54.2 distribute-list 102 out | default-metric 70 | ! | access-list 102 deny 172.16.0.0 0.7.255.255 255.252.0.0 0.3.255.255 | access-list 102 deny 192.168.50.0 0.0.0.255 255.255.255.128 0.0.0.127 An alternate method is via network and route statements: router bgp 64100 no synchronization network 172.16.0.0 mask 255.248.0.0 network 192.168.50.0 mask 255.255.255.0 neighbor 192.168.54.2 remote-as 65000 neighbor 192.168.54.2 default-metric 70 ip route 172.16.0.0 255.248.0.0 Null0 254 ip route 192.168.50.0 255.255.255.0 Null0 254 In this case, only those routes explicitly mentioned in "network" statements will be announced with BGP. For these routes to be announced, there has to be a corresponding route in the IP forwarding table, thus the need to create the static routes. The static routes will also serve as "pull-ups" for the route advertisements and thus prevent route flapping: these routes will always be announced with BGP by this router. Note that as long as more specific routes exist internally in your network, these will be used in preference to the static "less specific" route entries (longest prefix matching is being used). A good rule to follow is to never redistribute IGP learnt routes directly into BGP, but to rather use network or aggregate-address statements. And if you must redistribute dynamically learnt IGP routes into BGP, you MUST use filtering. The reasons for this advice are several, some of which are: 1) if your IGP is classful (e.g. RIP or IGRP) you will by default not do any route aggregation 2) if you have an internal stability problem (accidents do happen), this will be reflected as a "route flap" in the whole routing system, globally burning CPU cycles better spent on other things 3) if the IGP -> BGP transition is unrestricted, this can lead to false routing information escaping from your network (especially if you do not fully have administrative control over your IGP) 6. What do all these /16s and /24s mean in my BGP tables? This refers to the number of bits of the network part of the IP address. A former class B may appear as 172.50.0.0/16, which is the same as 256 class C's which can appear as 192.200.0.0/16. A single class C appears as 192.201.1.0/24. These "things" are often called an "IP prefix", which consists of an IP address and a mask length. The mask length specifies the number of leftmost contiguous significant bits in the corresponding IP address. Thus, an IP prefix with a prefix length of 15 (denoted /15) covers the address space of 128k IP addresses, and a /17 covers the address space of 32k IP addresses. Here is a table of the more popular CIDR blocks: # of former CIDR class C block nets ---- ---- /27 1/8 /26 1/4 /25 1/2 /24 1 /23 2 /22 4 /21 8 /20 16 /19 32 /18 64 /17 128 /16 256 = 1 former class B /15 512 /14 1024 /13 2048 In general, advertising a prefix covering less address space than a /24 prefix will probably not get into the global routing tables, and global Internet connectivity is less likely to happen. Note that for you as an administrator of an AS, it is a good idea to announce as few prefixes as possible and to utilize the address space as much as possible. | A more comprehensive table came out in October 1995 as: | | RFC1860: Variable Length Subnet Table For IPv4 | | This RFC is being revised and a new one will be out shortly. 7. Do I need to carry the full Internet routing table? When would it be necessary? What routers on the Internet carry full routing tables and how much memory is needed? No you do not need to carry the full Internet routing table. If you are single-homed, meaning you have a single connection to an ISP, then all you need to do is point a default route to the ISP and tell your ISP not to send you the full routing table. If you are multi-homed, you will want to know which nets to route via connection A and which nets to route via connection B. The easiest way to do this is to request a partial routing table from one ISP - with those nets that are closest to them, and default everything else to the other ISP. This way your routing tables need not contain the entire Internet universe but only a small subset. The closer you get to the hub or nexus of the Internet, the larger your routing tables need to be. For example, those connected to public exchange points (like the NAPs, CIX, STIX, LINX, dGIX) in general, carry full routing tables and run without a default route. 8. What is there in the Internet to stop me from making a mistake and announcing via BGP an aggregate that is larger than the nets I am in charge of? In principle there is nothing to stop you. The responsibility falls on both ends of the BGP link - you are responsible to filter what you announce and the receiving end - if it has its act together - filters also what it *thinks* it should be hearing from you so as prevent mistakes on your part. Those sites that do not work with access lists and filters and just readily accept what is sent to them are just waiting for a problem to happen. Filtering can either be done at the IP network level or at the BGP path (BGP orgin AS) level. See question 20 below for details on a tool to assist in filtering. 9. Who has to renumber with CIDR ? Sites that move from one ISP to another, and who had been allocated addresses from their original ISP's CIDR block, in all likelihood will have to return those addresses as part of the move. The reason is to keep the number of prefixes in the global routing system within the limits of current technology. | For further hints and procedures for renumbering, see the PIER | (Procedures for Internet/Enterprise Renumbering) homepage at: | | http://www.isi.edu:80/div7/pier Specific questions ------------------ 10. I have a /16 but have registered parts of it as /24s in the RADB. I now want to CIDRize. The problem is parts of the /16s are missing and are routed via a different ASN. Can you explain how more specific routes override more general ones and will I hurt my routing if I just advertise the /16 and not a bunch of /20s and /21s? There are two aspects to the answer: 1) Real (BGP) world: Given there are several AS's sharing addresses out of a /16 prefix, every AS should advertise exactly those prefixes which it is really originating. However, if there is one AS "originating" a significant majority of this address space, the concerned AS's might agree that this one and only advertises the /16 and all others their more specifics. The more specifics always take precedence over the less specific. 2) Routing registry: The registry DB, of course, should always reflect reality. If in the above example the AS's agree on the "big AS" announcing the /16, the "big AS" should document with the route-object that it's not really originating the whole aggregate by using "hole" attributes (see ripe.181, 5. The Route Object). 11. How can I redistribute our IGP routes (IGRP) so that they become aggregated when sent out via BGP? It is strongly discouraged to redistribute IGPs into BGP, because local IGP configuration errors might easily corrupt routing information of the whole Internet. If, however, you have to do it anyway, you MUST use strict distribute-lists with explicit permits (or route-maps) for redistribution. Here is an example for a Cisco configuration: router bgp 64100 aggregate-address 192.168.0.0 255.255.192.0 summary-only aggregate-address 172.16.0.0 255.254.0.0 summary-only redistribute igrp 64100 route-map origin-AS64100 ! ! or: ! redistribute igrp 64100 ! distribute-list 10 out igrp 64100 ! route-map origin-AS64100 permit 10 match ip address 10 ! access-list 10 permit 192.168.0.0 0.0.63.0 access-list 10 permit 172.16.0.0 access-list 10 permit 172.17.0.0 This example would generate one route 192.168/18 and one route 172.16/15 if any of the contained networks is in the IGP. 12. I am multihomed to three ISPs and can only CIDRize to two of them but to the third I need to still announce specific nets. What damage will this do to my AS? No damage can be done if the non-CIDR peer does not further announce your specifics to the global Internet. If your non-CIDR ISP DOES announce your specifics to the global Internet those specifics will have preference over the less specifics and therefore all traffic to you will get routed through the non-CIDR ISP. 13. I don't want to CIDRize. Can someone do proxy aggregation for me? Proxy aggregation should only be done with great care and should be avoided if you are not single-homed ! If you are single-homed ask your ISP. Others may proxy aggregate over your address range without your consent, and send your traffic over paths/links not of your choosing. Use of Routing Registries may help to identify and correct these problem areas. 14. What routers on the market today do support CIDR (classless routing)? Routers that are capable of handling CIDR are: - all Cisco routers running 10.0 or higher - all Bay Networks routers running 8.01 or higher - 3Com Netbuilder II and Netbuilder Remote Office - Telebit EMPB - Unix w/ BSD/OS 2.0 w/ gated 3.5alpha_11 + radix-fixes - IBM 2210 routers 15. How do I reach other parts of a subnetted old-style network when I have only partial routing information for that same old-style network?" There are actually three ways to solve this particular problem with Cisco's software. Which of them applies will depend on what software version is involved: o Preferred solution: turn on "ip classless" in your routers and use a default route inside your AS. The "ip classless" command prevents the existence of a single "subnet" route from blocking access via the default route to other subnets of the same old-style network. o Workaround for 9.1 or later software where the "ip classless" command is not available: install a "default network route" like this: "ip route 39.0.0.0 255.0.0.0 next-hop" along the axis your default route would normally take. o Workaround for 9.0 or older software: create a "default subnet route": "ip route 39.x.y.0 next-hop" combined with "ip default-network 39.x.y.0", otherwise as the 9.1 fix. Both of the latter solutions rely on static routes, and in the long run these will be impossible to maintain. In some topologies the use of static routes can be a problem (e.g. if you have more than one possible exit point from your AS to choose from). Supplemental information ------------------------ The following information is presented as supplemental information that is related to the CIDRization process. 16. What is the Internet Routing Registry? The IRR is a way for ASN's to publicize their own intended routing policies without having to request a change from a go-between. The RAdb which stands for the Routing Arbiter Data Base, which is part of the IRR, is part of a joint project between Merit and ISI. For full details contact: http://www.ra.net/routing.arbiter/RA/index.html. The Routing Arbiter is a project of the US National Science Foundation. As part of that project, it runs a routing registry database. That database (the RAdb) forms part of the IRR collection of databases. The RIPE database is not part of the RAdb but does participate in the IRR. At present, there are five entities that contribute to the IRR effort and more are expected. Today, all the contributing registries use the RIPE-181 database format. All IRR participants can be contacted via automail handlers that accept batch updates via email. An example of a routing update appears below: password: xxxxxxxx *rt: 138.134.0.0/16 *de: NET-IEC *or: AS378 *mb: AS378-MNT *ch: hank(a)aristo.tau.ac.il 950724 *so: RIPE The *rt: tag identifies the net and the routing policy is based on *or: tag. An example of a routing policy is presented below: aut-num: AS378 descr: ILAN descr: Israeli Academic and Research Network as-in: from AS1755 100 accept ANY as-in: from AS174 100 accept ANY as-in: from AS3339 100 accept AS3339 as-out: to AS1755 announce AS378 AS3339 as-out: to AS174 announce AS378 AS3339 as-out: to AS3339 announce ANY default: AS174 10 default: AS1755 20 default: AS3339 30 guardian: HANK(a)vm.biu.ac.il mnt-by: AS378-MNT admin-c: Hank Nussbacher tech-c: Hank Nussbacher changed: hank(a)vm.tau.ac.il 950627 source: RIPE For further details read over ripe-120.ps, ripe-121.ps and ripe-181.ps (via anonymous ftp from info.ripe.net/ripe/docs) |17. Are there any statistics available as to aggregation in the | Internet? | COUNTS OF RADB PREFIXES BY LENGTH - The number of Route objects | registered in the RADB, with active and withdrawn routes listed | by prefix length. Data from the current week is available from: | | ftp://ftp.ra.net/routing.arbiter/radb/reports/ | counts-by-prefix/Summarize_prefix.current | | Reports from previous weeks are available from: | | ftp://ftp.ra.net/routing.arbiter/radb/reports/ | counts-by-prefix/summarize_prefix.yymmdd | | IRR ROUTES SUMMARIZED BY PREFIX LENGTH WITH AGGREGATION - A | summary of unique prefixes registered in the IRR. Routes are | summarized by the first octet of the network number. If routes | within a prefix can be aggregated, a count is printed for each | prefix length that has a different count after aggregation. Data | from the current week is available from: | | ftp://ftp.ra.net/routing.arbiter/radb/reports/ | IRR_profile/IRR_Profile.current | | Reports from previous weeks are available from: | | ftp://ftp.ra.net/routing.arbiter/radb/reports/ | IRR_profile/IRR_Profile.yymmdd 18. How do I update the registered routing information for my ASN? You need to submit a "route" object update and perhaps an "aut-num" object update (see examples above). Route objects add new nets to your autonomous system (or you can remove nets from your autonomous system) and the Autonomous-system object describes the type of routing you wish to have. 19. Which Routing database takes precedence? RIPE? RADB? MCI? Do I have to update all of them? Each provider is allowed to select the preference order for authentic data. For example, ANS uses the following precedence: ANS, CANET, MCI, RIPE, RADB If there are two routes (with different origins) within one database, the changed date is used as a tiebreaker. Else, only database precedence is used. Thus, if the RADB entry has a more recent changed date than the RIPE, ANS will use the RIPE entry. You should only have to register in one of the IRR component databases. | There is a report which shows all routes in the RADB for a specified | AS and whether there are any duplicate routes in other IRR | registries or any aggregates which cover the route (in any of the | registries, including the RADB): | | http://www.ra.net/cgi-bin/ra/radb-duplicates.pl 20. How do I check what is registered in the IRR? The tool to use is whois. A few examples make the command self explanatory: whois -h whois.ra.net 128.228.0.0 whois -h whois.ripe.net as378 whois -h whois.canet.ca 142.77.0.0 | There is an easy Web interface to query and update the IRR: | | http://nap-roma.uni.net/cgi-bin/whois 21. Is there a tool to automatically create route filters based on IRR information? rlc is a route list compiler which is a subset of nlc/alc that allows the generation of route based filters (cisco access- lists) by extracting the nets belonging to an AS or AS MACRO from a routing database (i.e. Ripe Routing Database). In addition, it supports a limited set of functions to generate AS based filter lists. rlc is fully classless, and hence supports CIDR routes and subnets, as well as host routes. Source: ftp://dxcoms.cern.ch/pub/ripe-routing-wg Author: Jean-Michel Jouanigot, CERN <jimi(a)dxcoms.cern.ch> |22. What other tools are available in the CIDR world? | A web version of this information can be located at: | http://www.ra.net/~ra/tools | | ------------------------ | Online Tools and Reports | ------------------------ | | IRRWeb | | This graphical interface into the Internet Routing Registry makes | it possible to use the Web to query the IRR and update RADB AS | objects, Route objects, and Maintainer objects. Users can enter | any value that can be submitted through a whois query, such as an | AS number, network IP address, or maintainer. IRRWeb then displays | the corresponding AS objects, Route objects, or Maintainer objects | from the various registries in the IRR. Authorized maintainers can | edit the objects directly; IRRWeb performs a cursory pre-check and | mails the revised object to auto-dbm(a)ra.net. The user then | receives e-mail from auto-dbm confirming and displaying the revised | object, or explaining why the object was rejected. | | See http://www.ra.net/cgi-bin/ra/query-radb.pl | | Source code is available at | ftp://ftp.ra.net/routing.arbiter/tools/irrweb.tar.gz | | | Route History Server | | The Route History Server provides a mechanism for tracking | the announce/withdraw history of a given prefix for the last 24 | hours. The History Server peers with the route servers at | each NAP and records all BGP updates in History Server/Route | Server peering session. | | See http://www.ra.net/cgi-bin/ra/rshist.pl | | | ----------------------- | Tools Available for FTP | ----------------------- | | RSd | | The Route Server daemon (RSd) is an enhanced version of | the GateD routing software that provides multiples views of | routing information. | The software provides a mechanism for network service provides | to off-load the computational complexity of routing policy | calculations from their routers. RSd supports configuration and | transparent passing of BGP MEDs. The software also supports | BGP route flap dampening. | | Available at ftp://ftp.ra.net/routing.arbiter/tools/rsd.tar.gz | | | Peval | A policy evaluator that inputs a RIPE-181 policy | expression, performs essential background | calculations such as symbolic evaluations and | expansions, and outputs another RIPE-181 policy | expression that is used by other tools, such as | RTConfig. | | Available as part of the RAToolSet at | ftp://ftp.ra.net/routing.arbiter/tools/RAToolSet | | | RTConfig | A router configuration tool that can be used by | providers to generate router configs directly from | the RADB or other IRR registries. Currently in | production use for the RA Route Servers, ANSNET, and | CA*net, RTConfig is a front-end tool that uses peval | and radbserver transparently to users. | | Available as part of the RAToolSet at | ftp://ftp.ra.net/routing.arbiter/tools/RAToolSet | | | rrc2r/rrmerge | This Cisco-to-RIPE-181 conversion package makes it possible for | users to convert Cisco router configuration files to RIPE-181 | objects that can be submitted to the Internet Routing Registry | (IRR). The Cisco access-list can be converted into an explicit set | of nets embedded in an AS object or represented as a community. | The RADBserver is queried for any missing or previously registered | information. | | Available at | ftp://ftp.ra.net/routing.arbiter/tools/RAToolSet/rrc2r-0.2.tar.gz | | | CiscoBGP | IRR users have long recognized the need for tools that check the | IRR against routes actually propagated in the Internet. CiscoBGP | obtains and analyzes routing information from production Ciscos, | and compares the data with routes in the IRR. The software also | flags prefixes that are reserved by RFC 1597, Address Allocation | for Private Internets. | | Available as part of the MRT software distribution at | http://www.merit.edu/~mrt | | | BGPCheck | BGPCheck obtains and analyzes routing information from BGP4 | peering sessions, and compares the data with routes in the IRR. The | software also flags prefixes that are reserved by | RFC 1597, <em>Address Allocation for Private Internets</em>. | | Available as part of the MRT software distribution at | http://www.merit.edu/~mrt | | | PRtraceroute | The 'prtraceroute' tool is a powerful form of traceroute that | displays the Autonomous Systems that a packet traverses. | PRtraceroute was developed by the Pride project. | | A version of prtraceroute that queries the RADB is available at | ftp://ftp.ra.net/routing.arbiter/pride/prtraceroute-2.0beta2.shar.gz | | | ------------------ | Tool Announcements | ------------------ | PGP-Based Radb Authentication | Follow these steps to take advantage of the new RADB support for | PGP-based digital signatures: | | 1. Register your public key with the Routing Arbiter Service. | 2. Modify your Maintainer object to reflect your use of digital | signatures. | 3. Use PGP to sign your RADB transactions. | | For detailed instructions, see: | http://www.ra.net/routing.arbiter/RA/RADB.tools.docs/pgp.html Contributors: Christian Panigl - Vienna University, Austria Bill Manning - ISI Tony Li - Cisco Systems Havard Eidnes - SINTEF, Norway Yakov Rekhter - Cisco Systems | Craig Labovitz - Merit Network

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99 and 44/100 % pure... [Re: outages, quality monitoring, trouble tickets, etc]
by sgoldste＠nsf.gov 28 Nov '95

28 Nov '95

At 3:03 PM 11/27/95, Jon Zeeff wrote: >Being in the web hosting business, we measure our own "availability" >and that of others. The top providers do 99.9%.... I recall having calculated several years back that ~4 hours of unavailability (to customers) per 30-day month implies 99.44% availability, an Ivory tower number to be sure (are there any of you out there old enough to remember the incessant ad's for Ivory Soap "99 and 44/100 percent pure"?). Sprint proposed such a number to NSF back in 1989 for the international services under the International Connections Management (ICM) agreement. One thing we both learned along the way was that there are factors beyond any carrier's abiolity to control, especially in international (read "multi-player") services. So, for example, when a cisco box needed re-powering in Stockholm or London, but the local staff was gone for the night and nothing would happen until morning, or when the physical circuit passed through Amsterdam or Germany, and a line break depended on PTT Netherlands or Deutsche Telekom to repair, could/should we hold Sprint responsible? We decided to ask Sprint to produce numbers that related to the portion of the end-to-end linnk under their direct control, e.g., ICM box in Washington to ICM box at London demarc. The numbers, of course, looked a lot better. (I cannot recall them anymore.) But even then, we did not impose quality measures like packet drop rates (and, if we had, how could we know if they were caused by traffic congestion or by poor line quality if the link was heavily loaded almost all day?). Just to mudy the waters a bot more... --SG ____________________________________________ Steve Goldstein, National Science Foundation +1(703)306-1949 Ext. 1119 "Let's not procrastinate until tomorrow!"

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