02-07-2012 09:44 AM - edited 03-04-2019 03:10 PM
I have a weird BGP issue.
The issue is I see in the routing tables and BGP table the route and where it should be routing to from other locations, however, when I run a traceroute it does not go the direction I intend it to go every time. All output is below (I am sorry for the length but all details I thought were important.) Looking for a little help with why this traffic is acting the way it is?
I need to provide the output in order to understand what I am trying to say.
I am going to provide the route-views output as well as Global Crossing output for comparison.
We have 3 peers.
AS 13490
AS 3112
AS 600 (we have to sessions with this provider)
We prepend our own AS 2025 6 times to our peer AS 13490. Interestingly after looking at what we announce I do not see the pre-pending at all
route-map AS13490-OUT, permit, sequence 10
Match clauses:
ip address prefix-lists: AS2025-DORM-ADV
Set clauses:
Policy routing matches: 0 packets, 0 bytes
route-map AS13490-OUT, permit, sequence 20
Match clauses:
ip address prefix-lists: AS2025-ADV
Set clauses:
as-path prepend 2025 2025 2025 2025 2025 2025
Policy routing matches: 0 packets, 0 bytes
btsnoc11-br-01#sh ip prefix-list AS2025-ADV
ip prefix-list AS2025-ADV: 4 entries
seq 5 permit 131.183.0.0/16
seq 10 permit 136.x.x.x/16
seq 15 permit 206.x.x.x/24
seq 20 permit 198.x.x.x/23
btsnoc11-br-01#
router bgp 2025
no synchronization
bgp log-neighbor-changes
network 131.183.0.0
network 136.x.x.x
network 198.x.x.x
network 206.x.x.x
aggregate-address 198.x.x.x 255.255.254.0 summary-only
neighbor 72.x.x.x remote-as 13490
neighbor 72.x.x.x password 7 142201580F11387A303107
neighbor 72.x.x.x ebgp-multihop 10
neighbor 72.x.x.x send-community <--This will be removed, there is no community string configured for this peer.(cleaning up someone else mess)
neighbor 72.x.x.x soft-reconfiguration inbound
neighbor 72.x.x.x route-map AS13490-IN in
neighbor 72.x.x.x route-map AS13490-OUT out
btsnoc11-br-01#sh ip bgp neigh 72.240.XX.XX adv | i 131.183
*> 131.183.0.0 131.187.253.94 0 32768 i
btsnoc11-br-01#sh ip route 131.183.0.0
Routing entry for 131.183.0.0/16, 3 known subnets
Variably subnetted with 3 masks
S 131.183.222.0/23 [1/0] via 131.187.253.83
S 131.183.224.0/19 [1/0] via 72.241.59.153
S 131.183.0.0/16 [10/0] via 131.187.253.94
btsnoc11-br-01#sh run | i 131.187.253.94
ip route 131.183.0.0 255.255.0.0 131.187.253.94 10
ip route 136.247.0.0 255.255.0.0 131.187.253.94
ip route 136.247.24.0 255.255.248.0 131.187.253.94
The IP range is 131.183.0.0
route-views>sh ip bgp 131.183.1.253
BGP routing table entry for 131.183.0.0/16, version 2637983298
Paths: (36 available, best #5, table Default-IP-Routing-Table)
Not advertised to any peer
3549 3356 13490 2025
208.51.134.254 (inaccessible) from 208.51.134.254 (67.17.81.150)
Origin IGP, metric 1, localpref 100, valid, external
3333 3356 13490 2025
193.0.0.56 from 193.0.0.56 (193.0.0.56)
Origin IGP, localpref 100, valid, external
19214 2828 3356 13490 2025
208.74.64.40 from 208.74.64.40 (208.74.64.40)
Origin IGP, localpref 100, valid, external
701 209 600 2025
157.130.10.233 from 157.130.10.233 (137.39.3.60)
Origin IGP, localpref 100, valid, external
3356 13490 2025
4.69.184.193 from 4.69.184.193 (4.68.3.50)
Origin IGP, metric 0, localpref 100, valid, external, best
Community: 3356:3 3356:22 3356:100 3356:123 3356:575 3356:2035
2914 3356 13490 2025
129.250.0.11 from 129.250.0.11 (129.250.0.12)
Origin IGP, metric 6, localpref 100, valid, external
Community: 2914:420 2914:1008 2914:2000 2914:3000 65504:3356
1668 3356 13490 2025
66.185.128.48 from 66.185.128.48 (66.185.128.48)
Origin IGP, metric 2, localpref 100, valid, external
852 174 13490 2025
154.11.98.225 from 154.11.98.225 (154.11.98.225)
Origin IGP, metric 0, localpref 100, valid, external
Community: 852:180
2828 209 13490 2025
65.106.7.139 from 65.106.7.139 (66.239.189.139)
Origin IGP, metric 3, localpref 100, valid, external
852 174 13490 2025
154.11.11.113 from 154.11.11.113 (154.11.11.113)
Origin IGP, metric 0, localpref 100, valid, external
Community: 852:180
7500 2516 3356 13490 2025
202.249.2.86 from 202.249.2.86 (202.249.2.86)
Origin IGP, localpref 100, valid, external
1239 3356 13490 2025
144.228.241.130 from 144.228.241.130 (144.228.241.130)
Origin IGP, localpref 100, valid, external
3277 3267 50139 20965 11537 3112 2025
194.85.102.33 from 194.85.102.33 (194.85.4.4)
Origin IGP, localpref 100, valid, external
Community: 3277:3267 3277:65100 3277:65320 3277:65326 3277:65330
5459 174 13490 2025
195.66.232.239 from 195.66.232.239 (195.66.232.239)
Origin IGP, localpref 100, valid, external
Community: 5459:1 5459:60
3561 174 13490 2025
206.24.210.102 from 206.24.210.102 (206.24.210.102)
Origin IGP, localpref 100, valid, external
3267 50139 20965 11537 3112 2025
194.85.40.15 from 194.85.40.15 (193.232.80.7)
Origin IGP, localpref 100, valid, external
286 174 13490 2025
134.222.87.1 from 134.222.87.1 (134.222.85.99)
Origin IGP, localpref 100, valid, external
Community: 286:18 286:19 286:28 286:29 286:49 286:800 286:888 286:3031
3257 174 13490 2025
89.149.178.10 (inaccessible) from 89.149.178.10 (213.200.87.91)
Origin IGP, metric 10, localpref 100, valid, external
Community: 3257:8012 3257:30153 3257:50001 3257:54900 3257:54901
6453 209 13490 2025
66.110.0.86 from 66.110.0.86 (66.110.0.86)
Origin IGP, localpref 100, valid, external
16150 174 13490 2025
217.75.96.60 from 217.75.96.60 (217.75.96.60)
Origin IGP, metric 0, localpref 100, valid, external
Community: 174:21001 174:22013 16150:63392 16150:65320 16150:65326
7660 22388 11537 3112 2025
203.181.248.168 from 203.181.248.168 (203.181.248.168)
Origin IGP, localpref 100, valid, external
Community: 7660:10 7660:3000 11537:950 22388:100
2497 209 13490 2025
202.232.0.2 from 202.232.0.2 (202.232.0.2)
Origin IGP, localpref 100, valid, external
1221 4637 174 13490 2025
203.62.252.186 from 203.62.252.186 (203.62.252.186)
Origin IGP, localpref 100, valid, external
6079 11164 600 2025
207.172.6.1 from 207.172.6.1 (207.172.6.1)
Origin IGP, metric 0, localpref 100, valid, external
812 11164 600 2025
64.71.255.61 from 64.71.255.61 (64.71.255.61)
Origin IGP, localpref 100, valid, external
6079 11164 600 2025
207.172.6.20 from 207.172.6.20 (207.172.6.20)
Origin IGP, metric 0, localpref 100, valid, external
6539 11164 600 2025
66.59.190.221 from 66.59.190.221 (66.59.190.221)
Origin IGP, localpref 100, valid, external
4436 11164 600 2025
69.31.111.244 from 69.31.111.244 (69.31.111.244)
Origin IGP, metric 0, localpref 100, valid, external
Community: 4436:21216 11164:1140 11164:7500 11164:51240 11164:52100 11164:52200
6939 11164 600 2025
216.218.252.164 from 216.218.252.164 (216.218.252.164)
Origin IGP, localpref 100, valid, external
7018 3356 13490 2025
12.0.1.63 from 12.0.1.63 (12.0.1.63)
Origin IGP, localpref 100, valid, external
Community: 7018:5000
3303 174 13490 2025
164.128.32.11 from 164.128.32.11 (138.187.128.158)
Origin IGP, localpref 100, valid, external
Community: 3303:1004 3303:1006
22388 11537 3112 2025
192.203.116.253 from 192.203.116.253 (192.203.116.253)
Origin IGP, localpref 100, valid, external
Community: 11537:950 22388:100
8075 174 13490 2025
207.46.32.34 from 207.46.32.34 (207.46.32.34)
Origin IGP, localpref 100, valid, external
4826 6939 11164 600 2025
114.31.199.1 from 114.31.199.1 (114.31.199.1)
Origin IGP, metric 0, localpref 100, valid, external
101 101 11537 3112 2025
209.124.176.223 from 209.124.176.223 (209.124.176.223)
Origin IGP, localpref 100, valid, external
Community: 101:20200 101:20210 101:22210 11537:950
Extended Community: RT:101:22210
3582 4600 11537 3112 2025
128.223.253.10 from 128.223.253.10 (128.223.253.10)
Origin IGP, localpref 100, valid, external
Community: 3582:567 4600:99
route-views>
Global Crossing Output:
BGP routing table entry for 131.183.0.0/16, version 455605753
Paths: (25 available, best #20, table default)
Not advertised to any peer
3356 13490 2025, (received & used)
ge4-12-1000M.ar6.PHX1.gblx.net from loop0.ir1.ATL1.gblx.net
Origin IGP, metric 100, localpref 201, valid, internal
Community: 3549:2454 3549:30840 (North American; United States)
Originator: loop0.ar4.ATL2.gblx.net, Cluster list: 0.0.0.91
3356 13490 2025, (received & used)
ge4-12-1000M.ar6.PHX1.gblx.net from loop0.ir2.ATL1.gblx.net
Origin IGP, metric 100, localpref 201, valid, internal
Community: 3549:2454 3549:30840 (North American; United States)
Originator: loop0.ar4.ATL2.gblx.net, Cluster list: 0.0.0.91
3356 13490 2025, (received & used)
ge4-12-1000M.ar6.PHX1.gblx.net from loop0.ir1.JFK1.gblx.net
Origin IGP, metric 100, localpref 201, valid, internal
Community: 3549:2355 3549:30840 (North American; United States)
Originator: loop0.ar5.NYC1.gblx.net, Cluster list: 0.0.0.71
3356 13490 2025, (received & used)
ge4-12-1000M.ar6.PHX1.gblx.net from loop0.ir1.NYC1.gblx.net
Origin IGP, metric 100, localpref 201, valid, internal
Community: 3549:2355 3549:30840 (North American; United States)
Originator: loop0.ar5.NYC1.gblx.net, Cluster list: 0.0.0.71
3356 13490 2025, (received & used)
ge4-12-1000M.ar6.PHX1.gblx.net from loop0.ir1.CDG2.gblx.net
Origin IGP, metric 100, localpref 201, valid, internal
Community: 3549:2623 3549:31250 (Europe; France)
Originator: loop0.ar3.CDG2.gblx.net, Cluster list: 0.0.0.131
3356 13490 2025, (received & used)
ge4-12-1000M.ar6.PHX1.gblx.net from loop0.ir2.CDG2.gblx.net
Origin IGP, metric 100, localpref 201, valid, internal
Community: 3549:2623 3549:31250 (Europe; France)
Originator: loop0.ar3.CDG2.gblx.net, Cluster list: 0.0.0.131
3356 13490 2025, (received & used)
ge4-12-1000M.ar6.PHX1.gblx.net from loop0.ir1.AMS2.gblx.net
Origin IGP, metric 100, localpref 201, valid, internal
Community: 3549:2682 3549:31528 (Europe; Netherlands)
Originator: loop0.ar2.AMS1.gblx.net, Cluster list: 0.0.0.121
3356 13490 2025, (received & used)
ge4-12-1000M.ar6.PHX1.gblx.net from loop0.ir1.HAM1.gblx.net
Origin IGP, metric 100, localpref 201, valid, internal
Community: 3549:2724 3549:31276 (Europe; Germany)
Originator: loop1.ar4.FRA4.gblx.net, Cluster list: 0.0.0.141
3356 13490 2025, (received & used)
ge4-12-1000M.ar6.PHX1.gblx.net from loop0.ir2.AMS2.gblx.net
Origin IGP, metric 100, localpref 201, valid, internal
Community: 3549:2682 3549:31528 (Europe; Netherlands)
Originator: loop0.ar2.AMS1.gblx.net, Cluster list: 0.0.0.121
3356 13490 2025, (received & used)
ge4-12-1000M.ar6.PHX1.gblx.net from loop0.ir2.LON3.gblx.net
Origin IGP, metric 100, localpref 201, valid, internal
Community: 3549:2529 3549:31826 (Europe; United Kingdom)
Originator: loop1.ar9.LON3.gblx.net, Cluster list: 0.0.0.111
3356 13490 2025, (received & used)
ge4-12-1000M.ar6.PHX1.gblx.net from loop0.ir1.LON3.gblx.net
Origin IGP, metric 100, localpref 201, valid, internal
Community: 3549:2529 3549:31826 (Europe; United Kingdom)
Originator: loop1.ar9.LON3.gblx.net, Cluster list: 0.0.0.111
3356 13490 2025, (received & used)
ge4-12-1000M.ar6.PHX1.gblx.net from loop0.ir1.FRA4.gblx.net
Origin IGP, metric 100, localpref 201, valid, internal
Community: 3549:2724 3549:31276 (Europe; Germany)
Originator: loop1.ar4.FRA4.gblx.net, Cluster list: 0.0.0.141
3356 13490 2025, (received & used)
ge4-12-1000M.ar6.PHX1.gblx.net from loop0.ir1.SFO1.gblx.net
Origin IGP, metric 100, localpref 201, valid, internal
Community: 3549:2145 3549:30840 (North American; United States)
Originator: loop1.ar5.SJC2.gblx.net, Cluster list: 0.0.0.21
3356 13490 2025, (received & used)
ge4-12-1000M.ar6.PHX1.gblx.net from loop0.ir1.LAX1.gblx.net
Origin IGP, metric 100, localpref 201, valid, internal
Community: 3549:2022 3549:30840 (North American; United States)
Originator: loop0.ar2.LAX2.gblx.net, Cluster list: 0.0.0.11
3356 13490 2025, (received & used)
ge4-12-1000M.ar6.PHX1.gblx.net from loop0.ir1.MIA1.gblx.net
Origin IGP, metric 100, localpref 201, valid, internal
Community: 3549:2474 3549:30840 (North American; United States)
Originator: loop1.ar4.MIA2.gblx.net, Cluster list: 0.0.0.92
3356 13490 2025, (received & used)
ge4-12-1000M.ar6.PHX1.gblx.net from loop0.ir1.PAO2.gblx.net
Origin IGP, metric 100, localpref 201, valid, internal
Community: 3549:2145 3549:30840 (North American; United States)
Originator: loop1.ar5.SJC2.gblx.net, Cluster list: 0.0.0.21
3356 13490 2025, (received & used)
ge4-12-1000M.ar6.PHX1.gblx.net from loop0.ir1.PHI1.gblx.net
Origin IGP, metric 100, localpref 201, valid, internal
Community: 3549:2407 3549:30840 (North American; United States)
Originator: ar7.DCA3.gblx.net, Cluster list: 0.0.0.81
3356 13490 2025, (received & used)
ge4-12-1000M.ar6.PHX1.gblx.net from loop0.ir1.WDC2.gblx.net
Origin IGP, metric 100, localpref 201, valid, internal
Community: 3549:2407 3549:30840 (North American; United States)
Originator: ar7.DCA3.gblx.net, Cluster list: 0.0.0.81
3356 13490 2025, (received & used)
ge4-12-1000M.ar6.PHX1.gblx.net from loop0.ir1.PHX1.gblx.net
Origin IGP, metric 100, localpref 201, valid, internal
Community: 3549:2022 3549:30840 (North American; United States)
Originator: loop0.ar2.LAX2.gblx.net, Cluster list: 0.0.0.11 3356 13490 2025, (received & used)
ge4-12-1000M.ar6.PHX1.gblx.net from loop0.ir1.CHI1.gblx.net
Origin IGP, metric 100, localpref 201, valid, internal, best
Community: 3549:2205 3549:30840 (North American; United States)
Originator: loop0.ar5.CHI2.gblx.net, Cluster list: 0.0.0.41 3356 13490 2025, (received & used)
ge4-12-1000M.ar6.PHX1.gblx.net from loop0.ir2.MIA1.gblx.net
Origin IGP, metric 100, localpref 201, valid, internal
Community: 3549:2474 3549:30840 (North American; United States)
Originator: loop1.ar4.MIA2.gblx.net, Cluster list: 0.0.0.92
3356 13490 2025, (received & used)
ge4-12-1000M.ar6.PHX1.gblx.net from loop0.ir1.HOU1.gblx.net
Origin IGP, metric 100, localpref 201, valid, internal
Community: 3549:2296 3549:30840 (North American; United States)
Originator: 67.17.83.0, Cluster list: 0.0.0.61
3356 13490 2025, (received & used)
ge4-12-1000M.ar6.PHX1.gblx.net from loop0.ir1.DAL1.gblx.net
Origin IGP, metric 100, localpref 201, valid, internal
Community: 3549:2296 3549:30840 (North American; United States)
Originator: 67.17.83.0, Cluster list: 0.0.0.61
3356 13490 2025, (received & used)
ge4-12-1000M.ar6.PHX1.gblx.net from loop0.ir2.SEA1.gblx.net
Origin IGP, metric 100, localpref 201, valid, internal
Community: 3549:2176 3549:30840 (North American; United States)
Originator: loop1.ar6.SEA1.gblx.net, Cluster list: 0.0.0.31
3356 13490 2025, (received & used)
ge4-12-1000M.ar6.PHX1.gblx.net from loop0.ir1.SEA1.gblx.net
Origin IGP, metric 100, localpref 201, valid, internal
Community: 3549:2176 3549:30840 (North American; United States)
Originator: loop1.ar6.SEA1.gblx.net, Cluster list: 0.0.0.31
XO output:
show ip bgp 131.183.0.0
BGP routing table entry for 131.183.0.0/16, version 845319987
* * * Not advertised to any peer
2828 209 600 2025, (received & used)
216.156.2.165 from 216.156.2.165 (216.156.2.165)
Origin IGP, metric 2, localpref 100, valid, external
Traceroutes
rviews
route-views>traceroute 131.183.1.253
Type escape sequence to abort.
Tracing the route to 131.183.1.253
1 vl-51.uonet1-gw.uoregon.edu (128.223.51.2) [AS 3582] 0 msec 0 msec 0 msec
2 3.xe-1-3-0.uonet10-gw.uoregon.edu (128.223.3.10) [AS 3582] 0 msec 0 msec 0 msec
3 vl-105.ge-2-0-0.core0-gw.pdx.oregon-gigapop.net (198.32.165.89) [AS 4600] 0 msec 4 msec 4 msec
4 vl-101.abilene-losa-gw.oregon-gigapop.net (198.32.165.66) [AS 4600] 24 msec 28 msec 24 msec
5 xe-0-1-0.0.rtr.hous.net.internet2.edu (64.57.28.97) [AS 11537] 56 msec 60 msec 56 msec
6 64.57.28.113 [AS 11537] 80 msec 100 msec 120 msec
7 ae-8.10.rtr.wash.net.internet2.edu (64.57.28.7) [AS 11537] 96 msec 96 msec 92 msec
8 clevs-r0-xe-1-0-0s359.core.oar.net (192.88.192.137) [AS 3112] 100 msec 104 msec 100 msec
9 toldb-r9-xe-4-3-0s101.core.oar.net (192.153.39.14) [AS 3112] 128 msec 104 msec 104 msec
10 192.148.242.186 [AS 3112] 104 msec 100 msec 104 msec
11 * * *
12 * * *
savvis
traceroute to 131.183.1.253 (131.183.1.253), 30 hops max, 40 byte packets | |||
---|---|---|---|
Hop # | Router Name | IP Address | Time |
1 | ges1.Phoenix3px.savvis.net | 208.172.225.1 | 0.654 ms |
2 | acr1-ge-7-2-0.phoenix3px.savvis.net | 208.172.227.9 | 0.542 ms |
3 | cr2-pos-0-3-2-2.losangeles.savvis.net | 204.70.193.234 | 10.159 ms |
4 | 205.171.1.13 | 205.171.1.13 | 10.023 ms |
5 | 205.171.32.9 | 205.171.32.9 | 9.853 ms |
6 | 67.14.8.86 | 67.14.8.86 | 60.318 ms |
7 | 208-47-34-194.dia.static.qwest.net | 208.47.34.194 | 66.847 ms |
8 | core2.buckeyecom.net | 72.240.0.205 | 99.830 ms |
02-07-2012 10:06 AM
Did you cleared bgp session after as-path prepend configuration?
02-07-2012 10:11 AM
I had asked the people here who set this up and they beleive that it had been done already. This is something I needed to do for another change I just made. I will need to schedule that for our maint. window.
02-07-2012 10:19 AM
I think you don't need to schedule maintaince window to try this one:
clear ip bgp 72.x.x.x soft out
because soft reconfigration outboutn wouldn't lead to downtime.
Please let me know.
Also please be aware of filtering of excessive prepends by upstpream ISPs:
http://wiki.nil.com/Filter_excessively_prepended_BGP_paths
Please rate if it was helpful. "Correct answer" will be also helpful. Thank you.
02-08-2012 10:03 AM
I had already done that and no change.
I will reply back once changes have been made and bgp session has been hard cleared.
02-08-2012 11:21 AM
Are you weighting your routes?
02-08-2012 11:24 AM
There are couple of attributes that is currently configured, local pref and the as prepend.
I am at the point of reconfiguring it all after I have an understanding of what the organization is wanting to accomplish. This way it will clean up the mess from a previous employee who may or may not have had much understanding of BGP.
02-08-2012 11:36 AM
Lol yeah, sounds about right
Might be an idea.
Discover and save your favorite ideas. Come back to expert answers, step-by-step guides, recent topics, and more.
New here? Get started with these tips. How to use Community New member guide