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how to know if my bgp neighbour advertised my subnet or not ???

hi ,

i want to ask , 

how to know if my bgp neighbour advertised my network from his side or not ???

here is my config :

============================================================================

Gateway7600#sh ip bgp

BGP table version is 8, local router ID is 192.168.40.3

Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,

              r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,

              x best-external, a additional-path, c RIB-compressed,

Origin codes: i - IGP, e - EGP, ? - incomplete

RPKI validation codes: V valid, I invalid, N Not found

     Network          Next Hop            Metric LocPrf Weight Path

r>  0.0.0.0          a.a.56.165           0             0 xxxx i

*>  x.x.64.0/23   10.160.150.1             0         xxxx i

*>  y.y.19.192/27  10.160.150.5             0         3xxxx i

============================================================================

Gateway7600#sh running-config  | s bgp

router bgp zzz

bgp log-neighbor-changes

network x.x.64.0 mask 255.255.254.0

network y.y.19.192 mask 255.255.255.224

neighbor a.a.56.165 remote-as aaaaa

Gateway7600#

============================================================================

Gateway7600#sh ip bgp neighbors a.a.56.165 advertised-routes

BGP table version is 8, local router ID is 192.168.40.3

Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,

              r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,

              x best-external, a additional-path, c RIB-compressed,

Origin codes: i - IGP, e - EGP, ? - incomplete

RPKI validation codes: V valid, I invalid, N Not found

     Network          Next Hop            Metric LocPrf Weight Path

*>  x.x.64.0/23   10.160.150.1             0         32768 i

*>  y.y.19.192/27  10.160.150.5             0         32768 i

Total number of prefixes 2

============================================================================

note that the problem in the network 

y.y.19.192/27   <======== only

the network

x.x.64.0/23

is ok and no problems .

my question is , how to know if the my neighbour advertised my network

y.y.19.192/27

to the internet or not ???

can i test it  from my local  router ???

i searched the  site :

http://service.dic.at/cgi-bin/lg.cgi

and my subnet /27 is not shown !!!!!!!!!!!

plz help

regards

5 REPLIES 5
Highlighted
Cisco Employee

sh ip bgp neighbors a.a.56.165 advertised-routes is the right command to check

Normally /27 routes will get summarized at ISP level. So you should see your prefix with /24 prefix-length or smaller when you look at public route servers

The best way is to check to ping your IP reachability from internet

Also your immedaite ISP should be able to tell you if they have received your /27 advertisement

Thank you

Raju

Highlighted

hi

Raju

thanks for your reply

look, i have have two isps .

======================================

i would like to say that i advertised the network 

y.y.16.0/22  

but note i advertised it summarized  /22 but from another isp  and i set a specific attributes for the subnet /22

now i want to advertise only  /27  which is part of    /22    in another isp

the problem is   when i look for the subnet  /27 ips=========>

it only give me the bgp summary about /22   and not /27

i mean it is supposed to give me two results

one from /22 advertise

and  another one from /27 advertise

!!!!!!!!!!!!!!!!!!!!!!!!!

should i contact my isp  and ask him if he performed a summarization ???

regards

Highlighted

advertising any prefix with prefix-length between /25 to /32 normally get summarized in ISP level

It may be your immedaite ISP or an upstream service provider

You can check with your ISP to see if they are receving your routes and if they are doing summarization

Thank you

Raju

Highlighted

HI ,

Thanks

Raju

for your precious info

i will contact my isp and ask him about this issue .

regards

Highlighted

You are welcome

Thank you

Raju

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