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dmayan
newbie
Topic Author
Posts: 26
Joined: Sun Nov 10, 2013 9:28 pm

BGP advertisements print doesn't match what's really published

Fri Sep 20, 2019 4:05 pm

Hi,

When printing the advertisements to our FNA cluster, I can see this:
[dmayan.r@CORE-CACHES] > /rou bgp advertisements print FNA.IPv6            
PEER     PREFIX               NEXTHOP          AS-PATH                                               ORIGIN     LOCAL-PREF
FNA.IPv6 2803:5440:ca::/64    2803:5440:fac...                                                       igp       
FNA.IPv6 2803:5440:face::/48  2803:5440:fac...                                                       igp       
FNA.IPv6 2803:5440:252::/48   2803:5440:fac...                                                       igp       
FNA.IPv6 2803:5440:ffff::/48  2803:5440:fac...                                                       igp       
FNA.IPv6 2803:5440:1::/48     2803:5440:fac...                                                       igp       
FNA.IPv6 2803:5440:cace::/48  2803:5440:fac...                                                       igp       
FNA.IPv6 2803:5440::/48       2803:5440:fac...                                                       igp       
FNA.IPv6 2803:5440:21::/48    2803:5440:fac...                                                       igp       
FNA.IPv6 2803:5440:ca::/48    2803:5440:fac...                                                       igp       
[dmayan.r@CORE-CACHES] >
But, if I capture the BGP traffic to the FNA cluster, and decode it with Wireshark, I see this as advertised:
Network layer reachability information (149 bytes)
    2803:5440::/48
    2803:5440:1::/48
    2803:5440:2::/48
    2803:5440:21::/48
    2803:5440:ca::/48
    2803:5440:ca::/64
    2803:5440:100::/48
    2803:5440:101::/48
    2803:5440:112::/48
    2803:5440:252::/48
    2803:5440:4053::/48
    2803:5440:4054::/48
    2803:5440:4055::/48
    2803:5440:4056::/48
    2803:5440:4059::/48
    2803:5440:4062::/48
    2803:5440:4065::/48
    2803:5440:4066::/48
    2803:5440:cace::/48
    2803:5440:face::/48
    2803:5440:ffff::/48
All on 6.44.5 CCR1072

What's going on with this Mikrotik? It caused a lot of headaches doing troubleshooting for a problem that didn't exist.

And the IP routes "There are too many routes" bug on Winbox that you never solved.

Thanks
 
faisali
Member Candidate
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Posts: 180
Joined: Fri Oct 08, 2010 5:11 am

Re: BGP advertisements print doesn't match what's really published

Thu Oct 03, 2019 5:01 am

Care to post the code of your filter ... i.e how are you controlling what you are advertising ?
 
dmayan
newbie
Topic Author
Posts: 26
Joined: Sun Nov 10, 2013 9:28 pm

Re: BGP advertisements print doesn't match what's really published

Thu Oct 03, 2019 5:03 pm

Care to post the code of your filter ... i.e how are you controlling what you are advertising ?
Hi Faisali,

Filters have nothing to do here. The problem is the router shows one thing on bgp/advertisements, and a is advertising a different thing, as the Wireshark capture on the BGP traffic shows.

thanks
 
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sri2007
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Location: Quito
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Re: BGP advertisements print doesn't match what's really published

Mon Oct 21, 2019 3:06 am

Hello, I've never seen that before, but just to be sure that your FNA is getting the prefixes, there is a way at the FNA partners portal where you can check all of the prefixes received at the Facebook servers (insights tab).

Also can you share your filters please? Have you tried by doing a resend action to those BGP peers? Is that related to IPv6 only or does it happens at IPv4 too?
MikroTik Support and Consultancy - Español / English +593 93 924 1262
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dmayan
newbie
Topic Author
Posts: 26
Joined: Sun Nov 10, 2013 9:28 pm

Re: BGP advertisements print doesn't match what's really published

Mon Oct 21, 2019 3:58 pm

Hi SRI !!

Yes, the FNA are receiving the prefixes that I see in the packets capture. This became supicious when I began to see prefixes in the FNAs that were not in the advertisements. This is not summarization as the FNA receive more prefixes than the declared by ROS.

Here is the only filter affecting the FNA peer. It discards a loopback address.
Flags: X - disabled 
 0   chain=FNA_OUT prefix=xx.yy.22.254 prefix-length=32 invert-match=no action=discard set-bgp-prepend-path=""
I will check for IPv4 leaks and update the post.

Thanks!
Hello, I've never seen that before, but just to be sure that your FNA is getting the prefixes, there is a way at the FNA partners portal where you can check all of the prefixes received at the Facebook servers (insights tab).

Also can you share your filters please? Have you tried by doing a resend action to those BGP peers? Is that related to IPv6 only or does it happens at IPv4 too?
 
texmeshtexas
newbie
Posts: 42
Joined: Sat Oct 11, 2008 11:17 pm

Re: BGP advertisements print doesn't match what's really published

Wed Oct 14, 2020 2:05 am

Anyone find a solution to this.
Have same problem with a CCR1072 on 6.46.7
advertisements print show nothing to upstream peer and the upstream is receiving the prefixes and traffic is flowing as expected.

Strange thing is we have another CCR1072 peering to the same upstream on a different circuit and it shows everything properly.

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