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Outages.
by mhirse＠UU.NET 09 Mar '98

09 Mar '98

There is a large number of outages that are the result of severe weather conditions in certain regions. MidWest is experiencing severe weather conditions at this time. We have trunks that are down. @ 15:40 MFS has a OC48 down that is affecting some of our sites. This might also be affecting other providors. Please make note. Mohamed A. Hirse Corporate Network Engineer UUNET Technologies, INC

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Boston space
by Brian Horvitz 09 Mar '98

09 Mar '98

Anybody have/know of some good colo space in Boston? Most important is access to Bell Atlantic Copper. I'd like to run some DSL stuff for my Boston customers (don't start with me on that one...). Brian Horvitz

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Chicago outage?
by Kevin Houle 09 Mar '98

09 Mar '98

Just called UUNET to ask why traffic from MSP1 to CHI1 is crawling. They said there is a WorldCom OC-12 outage in the Chicago area afecting CHI <-> DC traffic. Something weather related. UUNET ticket # 694960. We have a pipe to MCI in WillowSprings, and it is crawling as well. Chicago apears to be a congested place at the moment. Kevin

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Re: Some abuse detection hacks ...
by prue＠ISI.EDU 09 Mar '98

09 Mar '98

Avi Freedmans post with a perl script to look for network abuses a while back got me to thinking that a C program could be written to do what his scripts do in near real time, continuously, if desired. It is possible to get Cisco routers to dump netflow data records to a host. I modified a Cisco demonstration program called fdget.c to look at the netflow data records and search for illegimate default pointing or transit routing from unauthorized source AS's to unauthorized destination AS's. I have made this program available via anonymous ftp (not a URL) on venera.isi.edu in subdirectory mon. This directory is blind. You must know what files you wish to retrieve by exact name. The files of interest are: atack.c README.atack flowdata.h I hope that you find them useful. My thanks go to Cisco for letting me distribute this program even though most of the code was written by Cisco. So keep in mind any bugs are mine. Walt Prue Los Nettos USC/ISI

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Re: Sprint outage 980309
by Jay Stewart 09 Mar '98

09 Mar '98

> Anyone from Sprint care to publicly shed light on the 4 hour outage > this morning? > > -- > Joe Provo, Network Architect Four hours? My Sprintlink circuit has been down for over 5 hours, and still showing: 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec I hope they fix it soon. I'd rather not see it make six hours. . Jay Stewart Vice President Olympia Networking Services - "Olympia's Premier Internet Provider" Phone 360.753-3636 Fax 360.357.6160 http://www.olywa.net/

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ARIN Whois Update
by Kim Hubbard 09 Mar '98

09 Mar '98

Effective Sunday, March 8, 1998 all ARIN Point of Contact (POC) handles will have a -ARIN extension. This is being done to differentiate between the various registry handles. All POC handles currently listed in the ARIN database will have the -ARIN extension added to them and newly created ARIN handles will include -ARIN. Searching for POC handles in ARIN's Whois requires the addition of the -ARIN extension to the handle, e.g., JS1-ARIN. Handle queries that do not use the -ARIN extention will result in a "no matches found". When submitting templates to ARIN please include the -ARIN extension when listing a pre-existing POC handle. Thanks, Kim Hubbard American Registry for Internet Numbers

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RE: BGP Confederation config problem...
by Richard Parker 09 Mar '98

09 Mar '98

Andy, > We have a 4-memberAS confederation, each with two IBGP peers. The > arrangement looks sort of like an octagon. the "r" is AS3 is an > internal hop, not a BGP peer. > > _______ ______ > | R-----R---r | > | / | | | | > |AS2 R | |AS3 R | > ----|-- ----|- > | | > ____|__ ____|_ > |AS4 R | |AS1 R | > | \ | | / | > | R-------R | > ------- ------ > > The problem is this: How do you get BGP to choose the shortest > "AS PATH", since internal AS paths are ignored in selecting BGP > routes? Right now, to top router in AS4 will always choose a > route through (2 3 1) instead of (1), because it prefers > "external" routes (even external confederation routes) over > internal routes. > > So, when given a choice, the router on the distant side of the AS > will ALWAYS prefer the three-AS-hop path, because it is external. > Is there a way around this?!? Perhaps I'm misunderstanding your question, but I thought BGP considered AS_path length before considering whether the path was an external path or an internal path. According to the Cisco documentation, BGP uses the following criteria to select a path for a destination: 1. If the path specifies a next hop that is inaccessible, drop the update. 2. Prefer the path with the largest weight. 3. If the weights are the same, prefer the path with the largest local preference. 4. If the local preferences are the same, prefer the path that was originated by BGP running on this router. 5. If no route was originated, prefer the route that has the shortest AS_path. 6. If all paths have the same AS_path length, prefer the path with the lowest origin type (where IGP is lower than EGP, and EGP is lower than Incomplete). 7. If the origin codes are the same, prefer the path with the lowest MED attribute. 8. If the paths have the same MED, prefer the external path over the internal path. 9. If the paths are still the same, prefer the path through the closest IGP neighbor. 10. Prefer the path with the lowest IP address, as specified by the BGP router ID. So, I'm going to make the following assumptions: A. Your BGP configuration is correct, i.e. the routes to AS1 via AS2 don't have a larger weight or local preference. B. You don't have any connectivity problems, i.e. the BGP table in the top router in AS4 contains routes that follow both the (2 3 1) path and the (1) path to the networks in AS1. C. AS4 only originates routes to networks in AS4, not the entire BGP confederation, i.e. no explicit "network" statements for the networks in AS1 and no redistribution of IGP routes to AS1's networks into AS4's BGP table. If this is all true, then perhaps your problem is a "next hop" problem. A next hop problem can occur when the next hop for a BGP entry is unreachable via the IGP. In your example the direct routes to AS1 in the top router in AS4 would have as their next hop the external interface of the bottom router in AS4. So, are you running an IGP on the external interface of the bottom router in AS4? If you are not running an IGP on the external interface, then BGP is not selecting the direct routes to AS1 because they're being rejected due to rule 1 in the above table. If this is indeed the problem, make sure that when you go to fix the problem that you run the IGP on the external interface in "passive" mode so that the peer doesn't hear your IGP updates. -Richard ------------------------------------------------------------ Richard Parker Third Point Systems <richard_parker(a)thirdpoint.com> 2400 Broadway Ave. #D230 +1 (310) 829-5949 Santa Monica, CA 90404

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RE: BGP Confederation config problem...
by Dave Van Allen 09 Mar '98

09 Mar '98

>Avi Freedman suggested using a +1 metric when leaving each member-AS. (Thanks Avi!) But it doesn't seem to help - perhaps I didn't do it right. Did our friend Avi also suggest that you need to add: ! bgp always-compare-med ! ?? Best regards, David Van Allen - FASTNET(tm) / You Tools Corporation dave(a)fast.net (888)321-FAST(3278) http://www.fast.net FASTNET - Business and Personal Internet Solutions -----Original Message----- From: Andy McConnell [mailto:andym@nttlabs.com] Sent: Friday, March 06, 1998 1:02 PM To: nanog(a)merit.edu Subject: BGP Confederation config problem... I have a problem I cannot solve. If anyone is running confederations like mine, I would appreciate some help :-) We have a 4-memberAS confederation, each with two IBGP peers. The arrangement looks sort of like an octagon. the "r" is AS3 is an internal hop, not a BGP peer. _______ ______ | R-----R---r | | / | | | | |AS2 R | |AS3 R | ----|-- ----|- | | ____|__ ____|_ |AS4 R | |AS1 R | | \ | | / | | R-------R | ------- ------ The problem is this: How do you get BGP to choose the shortest "AS PATH", since internal AS paths are ignored in selecting BGP routes? Right now, to top router in AS4 will always choose a route through (2 3 1) instead of (1), because it prefers "external" routes (even external confederation routes) over internal routes. So, when given a choice, the router on the distant side of the AS will ALWAYS prefer the three-AS-hop path, because it is external. Is there a way around this?!? Avi Freedman suggested using a +1 metric when leaving each member-AS. (Thanks Avi!) But it doesn't seem to help - perhaps I didn't do it right. In fact, it doesn't look like the metrics are adjusted more than 1. for example, from AS2, the lower router sees every route outside of AS2 as having only metric 1! The top router in AS3 does not add 1 to the metrics it readvertises to AS2. I've been stewing over this problem for some time... I believe there is some clue that I've missed. Any help would be greatly appreciated! -Andy -- Andy McConnell fAf"fffB f}fbfRflf< Network Architect, NTT Multimedia Communications Laboratories Writing about music is like dancing about architecture.

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Sprint outage 980309
by Joe Provo - Network Architect 09 Mar '98

09 Mar '98

Anyone from Sprint care to publicly shed light on the 4 hour outage this morning? -- Joe Provo, Network Architect 508.229.8400 x3006 Network Operations Center Fax 508.229.2375 UltraNet Communications, Inc. <jprovo(a)ultra.net>

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Ed Kern's NAT talk from the Feb NANOG notes are now on line
by sob＠academ.com 09 Mar '98

09 Mar '98

There have been some questions to me about when this would be available. The answer is now! http://www.academ.com/nanog/feb1998/nat.html Enjoy. [Note: The rest of them are coming shortly. Hopefully, you will find them all there by 12 noon CST tomorrow.]

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