Community discussions

MikroTik App
 
derdeagle
just joined
Topic Author
Posts: 24
Joined: Sat Jun 30, 2018 6:58 pm

Learned BGP routes are not advertised to peers

Thu Jan 19, 2023 1:06 pm

I have two routers (cr01 and cr02) in the same location for redundancy purposes (using VRRP).
Some servers announce routes via BGP to the VRRP address of the routers. Those routes are learned, seen as active and traffic gets routed there.
[user@cr01] > /routing/route/print where bgp 
Flags: A - ACTIVE; b, y - COPY; +, B - BLACKHOLE
Columns: DST-ADDRESS, GATEWAY, AFI, DISTANCE, SCOPE, TARGET-SCOPE, IMMEDIATE-GW
    DST-ADDRESS    GATEWAY    AFI  DISTANCE  SCOPE  TARGET-SCOPE  IMMEDIATE-GW           
Ab+ 10.10.10.1/32  10.10.3.2  ip4       200     40            30  10.10.3.2%vl-1030-tools
                                                                  10.10.3.2%vrrp-tools   
 b+ 10.10.10.1/32  10.10.3.3  ip4       200     40            30  10.10.3.3%vl-1030-tools
                                                                  10.10.3.3%vrrp-tools   
The routing table for BGP addresses for cr02 is empty as expected at this time (VRRP IP is active on cr01).

Now I want to announce/advertise the learned BGP routes from cr01 to cr02 (and the other way around) but this does not succeed (unfortunately I cannot see why).
[user@cr01] > /routing/bgp/export 
# jan/19/2023 11:53:41 by RouterOS 7.7
# software id = x
#
# model = CCR2116-12G-4S+
# serial number = x
/routing bgp connection
add as=64601 disabled=no listen=yes local.address=10.10.99.253 .role=ebgp name=to_cr02.home output.network=test_host_anycast_dns remote.address=10.10.99.252 router-id=10.10.99.253 routing-table=main
add as=64600 listen=yes local.address=10.10.3.254 .role=ibgp name=from_net_tools remote.address=10.10.3.0/24 router-id=10.10.3.253

[user@cr02] > /routing/bgp/export 
# jan/19/2023 11:55:29 by RouterOS 7.7
# software id = x
#
# model = RB3011UiAS
# serial number = x
/routing bgp connection
add as=64602 disabled=no listen=yes local.address=10.10.99.252 .role=ebgp name=to_cr01.home output.network=test_host_anycast_dns remote.address=10.10.99.253 router-id=10.10.99.252
add as=64600 listen=yes local.address=10.10.3.254 .role=ibgp name=from_net_tools remote.address=10.10.3.0/24 router-id=10.10.3.252
For testing purposes I announced the routes from the server to both router IP addresses (.253 and .252) and that worked.

I have the following address list on both routers.
[user@cr01] > /ip/firewall/address-list/print where list="test_host_anycast_dns"
Columns: LIST, ADDRESS, CREATION-TIME
# LIST                   ADDRESS     CREATION-TIME       
;;; TEST anycast IP for DNS
0 test_host_anycast_dns  10.10.10.1  jan/18/2023 20:32:55
For the output.network I have also tried a net rather than a single IP address to sort this out. I used 10.10.10.0/24 before.

The BGP connections are there.
[user@cr01] > /routing/bgp/connection/print 
Flags: D - dynamic, X - disabled, I - inactive 
 0   name="to_cr02.home" 
     remote.address=10.10.99.252 
     local.address=10.10.99.253 .role=ebgp 
     listen=yes routing-table=main router-id=10.10.99.253 as=64601 
     output.network=test_host_anycast_dns 

 1   name="from_net_tools" 
     remote.address=10.10.3.0/24 
     local.address=10.10.3.254 .role=ibgp 
     listen=yes routing-table=main router-id=10.10.3.253 as=64600 

[user@cr02] > /routing/bgp/connection/print 
Flags: D - dynamic, X - disabled, I - inactive 
 0   name="to_cr01.home" 
     remote.address=10.10.99.253 
     local.address=10.10.99.252 .role=ebgp 
     listen=yes routing-table=main router-id=10.10.99.252 as=64602 
     output.network=test_host_anycast_dns 

 1   name="from_net_tools" 
     remote.address=10.10.3.0/24 
     local.address=10.10.3.254 .role=ibgp 
     listen=yes routing-table=main router-id=10.10.3.252 as=64600 
Unfortunately I couldn't help myself with the documentation or things I found on the internet.
Could somebody please point out what I am missing?
 
User avatar
mrz
MikroTik Support
MikroTik Support
Posts: 7041
Joined: Wed Feb 07, 2007 12:45 pm
Location: Latvia
Contact:

Re: Learned BGP routes are not advertised to peers  [SOLVED]

Thu Jan 19, 2023 1:19 pm

You have two different local ASes, which is considered to be two separate BGP instances. You need to run one instace (preferred) or enable output.redistribute=bgp
 
derdeagle
just joined
Topic Author
Posts: 24
Joined: Sat Jun 30, 2018 6:58 pm

Re: Learned BGP routes are not advertised to peers

Thu Jan 19, 2023 1:24 pm

Thank you very much! Using the output.redistribute=bgp flag did the trick.
Unfortunately I cannot (AFAIK) run only one instance because of the different prefixes used in the communication.

Who is online

Users browsing this forum: 4l4R1, Ahrefs [Bot], bashay8, dervomsee, Energizer, GoogleOther [Bot], jahieulislam, rogerioqueiroz and 81 guests