June 2003 - Test - lists.nanog.org

Telehouse broadway carriers, and Time Warner opinions...
by Steve Francis 04 Jun '03

04 Jun '03

Anyone recommend a quality ISP in Telehouse broadway, New York? We're looking for a direct gig ethernet handoff, with a 50M commit, to an ISP with local in building IP equipment (we don't want to pay local loop charges, nor be subject to MAN fiber cuts). There do not seem to be that many teir 1-ish (whatever that means) ISP s available there, which surprises me, so I wonder if I am just missing them. TimeWarner is ISP we are looking at - can anyone comment on their network, peerings, noc, etc? Thanks

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<sot> Experience with Opnet tools
by Rich Sena 04 Jun '03

04 Jun '03

Looking for opinions and experiences with Opnet. Please contact me off-list... Please no sales pitches from vendors... -- Rich Sena - ras(a)thick.net ThickNET Consulting "On the way to understanding; you understand, and forget."

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About the address allocation convention between ISPs
by Teng Fei 04 Jun '03

04 Jun '03

Hello everyone, I have a question about the convention of address allocation between ISPs. If a smaller ISP tries to establish connection with its provider, does this small ISP configure one of the interface on its boarder router using an IP address obtained from the provider, or it is the other way around, that is, the provider uses one of the IP address belongs to the customer to configure the provider's boarder router? I have this question because I am trying to identify the link between two organizations from traceroute measurements. How the addresses are allocated will affect the identification of the inter-domain link by exactly one hop. I am not sure if there is such a convention at all, or the address assignment is randomly decided according to the agreement between the customer and the provider? Since I know there are many seasoned network professionals on this mailing list, I think it might be a proper question to ask here. Would anyone kindly be willing to share your experience? Thank you very much! Sincerely Teng

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Censorship at ISP-Level / DNS-Tampering Paper
by Maximillian Dornseif 04 Jun '03

04 Jun '03

[link for this: http://md.hudora.de/blog/guids/53/53/5261415523775104.html] Dear (swinog | siug | nanog), I recently asked for input on using proxies and DNS for blocking Web content. After some great input from listsmembers and the work of dedicated reviewers I have put an preprint online: "Government mandated blocking of foreign Web content" can be found at http://md.hudora.de/publications/#blocking or directly at http://md.hudora.de/publications/200306-gi-blocking/200306-gi- blocking.pdf It tries to give an technical overview about censorship at ISP level. The relevance for network management are mainly the empirical results on DNS tampering which are summarized at http://md.hudora.de/blog/guids/53/53/5261415523775104.html . Basically providers using DNS to block Web content don't get it right and break all kinds of stuff. Besides the technical challanges - BIND's coarse granularity allowing basically only manipulations at zone level - I think we face serious policy challenges: When once starting with DNS tampering why not use it for commercial purposes. E.g. redirect people trying to access your competitors domains to your own stuff? Possibly government mandated blocking manages to finish off, what the ICANN-wars where not able to archive: destroy DNS as an unified namespace. Thanks again for all the input. Regards Max Dornseif -- Maximillian Dornseif - http://md.hudora.de/ Dipl. Jur., University of Bonn, Germany - ars longa, vita brevis!

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RE: About the address allocation convention between ISPs
by Teng Fei 04 Jun '03

04 Jun '03

Dear Mr. Maynard, Thank you very much! Sincerely Teng On Wed, 4 Jun 2003, Robert D. Maynard wrote: > Teng, > > See here for unnumbered interface information: > http://www.cisco.com/warp/public/701/20.html > > > > -Robert Maynard > Vice President of Network Operations > Alliance Information Systems, LLC > mailto:robert@ojai.net > > -----Original Message----- > From: owner-nanog(a)merit.edu [mailto:owner-nanog@merit.edu] On Behalf Of > Teng Fei > Sent: Wednesday, June 04, 2003 6:11 AM > To: Darin Wayrynen > Cc: nanog(a)merit.edu > Subject: Re: About the address allocation convention between ISPs > > > Dear Mr. Wayrynen, > > Thank you very much for your reply. What do you mean by "unnumbered > interfaces"? Also could you please confirm my question that if the > customer's address block was not obtained from the provider, it is also > a > convention that the provider will provider the /30 address for the > inter-domain link? > > >From the replys, it seems to me that there is no way to tell which > link is indeed the inter-domain link, if the two ASes are peers. But > for > customer-providers, I can guess with confidence. Could I get these > information from the IPSes' or PoP's website, about who are their > customers/peers? And how exactly the addresses were assigned? > > Sincerely > > Teng > >

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Re: About the address allocation convention between ISPs
by Teng Fei 04 Jun '03

04 Jun '03

Dear Mr. Fort, Thank you very much for your help! But there are cases the ISPs are providing connectivity, albeit the address block of the customer was not obtained from the provider. For example, my university use Cable and Wireless as the commercial provider but our address was not assigned by C&W. In such as case, is the interface addresses at both ends of the interdomain link also assigned by the larger ISP? Sincerely Teng On Tue, 3 Jun 2003, Andrew Fort wrote: > Hi Teng, > Every ISP I've worked at (3), and every ISP I've purchased service from (4), allocates link addressing (/30s) from its own pools, rather than making the customer provide the link addressing. (These parties are all in Australia, if that matters). > > As I understand it, this is 'the convention' (you purchase a service, the provider definately has addresses, so it has them to provide). > > The matter is less clear with private peering agreements, as both parties are generally ISPs and have address space of their own which could be used. > > In the cases I've been involved in, one party has decided to use its own space (maybe due to their IGP design, but either way it'll work), which happens > to have been the larger party in every case (don't know if that's by design or logic of the method of agreement). > > > >Subject: About the address allocation convention between ISPs > > From: Teng Fei <tfei(a)ipanema.ecs.umass.edu> > > Date: Tue, 3 Jun 2003 01:10:33 +0000 (UTC) > > To: <nanog(a)merit.edu> > > > > > >Hello everyone, > > > >I have a question about the convention of address allocation between ISPs. > >If a smaller ISP tries to establish connection with its provider, does > >this small ISP configure one of the interface on its boarder router using > >an IP address obtained from the provider, or it is the other way around, > >that is, the provider uses one of the IP address belongs to the customer > >to configure the provider's boarder router? > > > >I have this question because I am trying to identify the link between two > >organizations from traceroute measurements. How the addresses are > >allocated will affect the identification of the inter-domain link by > >exactly one hop. > > > >I am not sure if there is such a convention at all, or the address > >assignment is randomly decided according to the agreement between the > >customer and the provider? > > > >Since I know there are many seasoned network professionals on this mailing > >list, I think it might be a proper question to ask here. Would anyone > >kindly be willing to share your experience? Thank you very much! > > > >Sincerely > > > >Teng > > >

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Re: Clocking Sources (was NTp sources that work in a datacenter (was Re: Is latency equivalentto RTT?))
by Stewart, William C (Bill), RTSLS 04 Jun '03

04 Jun '03

Some of you are telecom types who think "Stratum 1" is telco clocking SONET/SDH/T1/E1 kind of timing that's 10**-11 accurate but doesn't know or care what time of day it is. Stratum 3/Stratum 4 SONET accuracy is a couple orders of magnitude lower. And wander (<10Hz) matters, but jitter doesn't matter much. Others of you are computer types who think "Stratum 1" is "A good NTP time-of-day source", and 10**-6 accuracy is good enough to keep your billing records consistant and the machines in your data center all showing the same time, though it's nice to do better. Stratum 2, 3, 4, ... is just machines that are N hops away from Stratum 1, so they're likely to accumulate jitter and constant differences from asymmetry, but not to particularly have problems with wander except if their Stratum 1 wanders. It happens that GPS can do both, though the telco people use cesium clocks steered by GPS as their building timing sources, rather than using raw GPS, of course. If the whole GPS system dies, the telco systems will gradually drift unless they rebuild the timing networks that it mostly replaced, but good clocks help. The NTP system, on the other hand, will respond by doing something like a bunch of ISPs getting feeds from tick and tock and distributing them, and if it drifts a bit it's really no tragedy.

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Re: Pesky spammers are using my mailbox
by Stewart, William C (Bill), RTSLS 04 Jun '03

04 Jun '03

It would be really bad form to use BGP to advertise a specific route to their hosts and DNS server, and if you're not a Tier 1 provider your advertisements would probably be blocked anyway. While using the main Bogon list isn't really appropriate either, it's a problem that's becoming increasingly common, and a list of stolen routes is almost the right kind of place for such a thing. Obviously it's hard to implement cleanly, without opening up things like a "double Joe Job" attack where the miscreant attacks a web server by joe-jobbing somebody who'd get the server put on the block list. I get a mild version of the spammers-using-my-name attack - spammers sending mail to a closed mailing list I manage, who get bouncegrams from the list-manager saying that their posting is delayed for moderator approval, and if they were from forged addresses I get the bounces from the bouncegrams.

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Thank you
by Pete Kruckenberg 03 Jun '03

03 Jun '03

Thank you to everyone who attended NANOG 28 in Salt Lake City. We enjoyed hosting the conference and hope you enjoyed your time in Salt Lake. See you in October. Pete.

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SUMMARY: BGP Analytics
by Timothy Brown 03 Jun '03

03 Jun '03

I want to thank everyone for the volume of responses I received on this topic. I was already aware of the work the Akamai and Sockeye keiretsus were doing with BGP analysis, but thanks for the pointers. I was also familiar with CAIDA's efforts. Nick Feamster and Dave Andersen (lcs.mit.edu) had input on a system they are involved with at http://bgp.lcs.mit.edu/. Zebra is used, with dumps of BGP data in MRTd format. This data is collected and stuffed into a database, which can be plotted or viewed as appropriate. This was, by far, the most common solution presented (with only minor variations). There appear to be several already prebuilt tools designed for dealing with data in MRTd format, both by lcs as well as other groups. Tim Rand (ohsu.edu) suggested Juniper's source- and destination-class-utilization features as effective methods for traffic coming from specific autonomous system paths. Our network isn't Juniper-based, but this is good information. Andre Gironda (eBay) suggested a dump of the BGP update messages using a tool like tcpdump, then replaying them to zebra, presumably to avoid zebra interaction directly with the core network. Several papers were suggested indirectly or directly discussing BGP analysis: http://citeseer.nj.nec.com/andersen02topology.html http://citeseer.nj.nec.com/wang02observation.html http://citeseer.nj.nec.com/pei02improving.html http://citeseer.nj.nec.com/463603.html For those with questions about what I sought to do, I was looking to perform some arbitrary plots of regular expressions over time; show me paths that look like ^AS(x)_AS(y)$ [that are defined as best path] as opposed to ^AS(y)$ [that are not defined as best path] and graph the acceptance of those paths based on other factors (local preference, etc). For instance, if I was choosing transit via AS(x) for destination AS(y), even though I was directly connected to AS(y), i'd want to know for how many paths I was doing that for. In an ideal world, this data would be available via SNMP (for easy integration with existing toolsets). There are, of course, a ton of other analyses people want to do with BGP (some of which are even getting done). I've decided to build my own toolset for these purposes, building on the work of the concepts presented above. If you are an interested developer or would like to contribute some time to developing such an open-source toolset, please contact me off-list. Thanks again for all the input. Best regards, Tim

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