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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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WorldCom Fiber Cut
by Steve Noble 08 Mar '98

08 Mar '98

WorldCom is reporting a fibercut in Atlanta affecting multiple DS3's no ETA at this time, crew's should be onsite now or soon.

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BGP Confederation config problem...
by Andy McConnell 07 Mar '98

07 Mar '98

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 アンディマッコネル Network Architect, NTT Multimedia Communications Laboratories Writing about music is like dancing about architecture.

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Re: DoS ATTACK IN PROGRESS
by Jim Warner 07 Mar '98

07 Mar '98

Alex Rubenstein wrote: networks being used to facilitate the smurk (i.e. COME ON PEOPLE, TAME YOUR GODDAMN ROUTERS) I am real sympathetic. But NANOG is just a mailing list. The folks that read it by and large have already tamed their routers. If you want to have an impact on this problem, you'll have to grab your telephone and start contacting specific sites and the follow up with email. I know this is a lot of work because that's what we did with the netflow data we got from our smurf attack. In our efforts we found generally: 1. It is pretty easy to get sites to fix this once you get their attention. Our success rate with a telephone was about 80 percent. You are in a real good position to get their attention when you can say 'Your site is attacking my network and it hurts.' 2. Federal networks are the most trouble. NASA is not very well organized. After many calls, we got attention at NASA-ames and JPL, but we could not figure out who at NASA-Goddard to talk to. Ragging on this list is probably within its charter. That's not the problem. It is simply not going to be effective. -jim warner, UC Santa Cruz

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Re: DoS ATTACK IN PROGRESS
by Alex Rubenstein 07 Mar '98

07 Mar '98

http://www.quadrunner.com/~chuegen/smurf/ On Fri, 6 Mar 1998, Tom T. Thai wrote: > recomendations regarding configuring routers to prevent these? I only > have a set of rules and am not sure if it's effective. What do you use? > > On Fri, 6 Mar 1998, Alex Rubenstein wrote: > > > > > We are currently under a Smurf attack. > >

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DoS ATTACK IN PROGRESS
by Alex Rubenstein 07 Mar '98

07 Mar '98

We are currently under a Smurf attack. The ip address being attack is 207.99.6.75 (a static ip user on my network) Any help would be appreciated networks being used to facilitate the smurk (ie: COME ON PEOPLE; TAME YOUR GODDAMN ROUTERS) SrcIf SrcIPaddress DstIf DstIPaddress Pr SrcP DstP Pkts B/Pk Et1/3 129.52.30.254 Hs2/0 207.99.6.75 01 0000 0000 25K 76 Et1/3 129.52.35.3 Se3/2 207.99.6.75 01 0000 0000 38K 76 Et1/3 129.52.35.4 Se3/2 207.99.6.75 01 0000 0000 38K 76 Et1/3 129.52.35.58 Se3/2 207.99.6.75 01 0000 0000 38K 76 Et1/3 129.52.35.92 Se3/2 207.99.6.75 01 0000 0000 33K 76 Et1/3 129.52.35.75 Se3/2 207.99.6.75 01 0000 0000 41K 76 Et1/3 129.52.35.241 Se3/2 207.99.6.75 01 0000 0000 34K 76 Et1/3 129.52.35.245 Se3/2 207.99.6.75 01 0000 0000 18K 76 Et1/3 129.52.35.232 Se3/2 207.99.6.75 01 0000 0000 40K 76 Et1/3 129.52.35.235 Se3/2 207.99.6.75 01 0000 0000 41K 76 Et1/3 129.52.35.238 Se3/2 207.99.6.75 01 0000 0000 42K 76 Et1/3 129.52.35.230 Se3/2 207.99.6.75 01 0000 0000 41K 76 Et1/3 129.52.34.81 Se3/2 207.99.6.75 01 0000 0000 31K 76 Et1/3 129.52.34.80 Se3/2 207.99.6.75 01 0000 0000 29K 76 Et1/3 129.52.34.79 Se3/2 207.99.6.75 01 0000 0000 26K 76 Et1/3 129.52.34.78 Se3/2 207.99.6.75 01 0000 0000 31K 76 Et1/3 38.1.53.236 Se3/0 207.99.6.75 01 0000 0000 3823 76 Et1/3 38.1.53.237 Se3/0 207.99.6.75 01 0000 0000 3813 76 Et1/3 38.1.53.238 Se3/0 207.99.6.75 01 0000 0000 3833 76 Et1/3 38.1.53.239 Se3/0 207.99.6.75 01 0000 0000 3801 76 Et1/3 38.1.53.233 Se3/0 207.99.6.75 01 0000 0000 3793 76 Et1/3 38.1.53.234 Se3/0 207.99.6.75 01 0000 0000 3827 76 Et1/3 38.1.53.235 Se3/0 207.99.6.75 01 0000 0000 3825 76 Et1/3 38.1.53.228 Se3/0 207.99.6.75 01 0000 0000 6414 76 Et1/3 38.1.53.229 Se3/0 207.99.6.75 01 0000 0000 4064 76 Et1/3 38.1.53.230 Se3/0 207.99.6.75 01 0000 0000 4130 76 Et1/3 38.1.53.231 Se3/0 207.99.6.75 01 0000 0000 3827 76 Et1/3 129.37.202.46 Se3/2 207.99.77.23 06 0502 0050 7 140 Et1/3 129.37.202.46 Se3/2 207.99.77.23 06 0503 0050 5 184 Et1/3 129.37.202.46 Se3/2 207.99.77.23 06 0500 0050 11 136 Et1/3 129.37.202.46 Se3/2 207.99.77.23 06 0501 0050 8 128 Et1/3 129.37.202.46 Se3/2 207.99.77.23 06 0504 0050 4 131

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