02-27-2020 05:43 PM
Haven't had to do this in a number of years and cannot get our new ISP to see any advertised routes for BGP.
Tried hacking away at prefix-lists, etc. but just cannot seem to get advertisements out.
It's got to be something staring me in the face but I just can't see it after a couple of days. Any ideas?
We're using this:
router rip
version 2
redistribute bgp 123456
network AAA.0.0.0
!
router bgp 123456
bgp router-id BBB.BBB.BBB.2
bgp log-neighbor-changes
network AAA.AAA.AAA.0 mask 255.255.255.0
redistribute rip
neighbor BBB.BBB.BBB.1 remote-as 174
!
ip route 0.0.0.0 0.0.0.0 BBB.BBB.BBB.1
!
!
ip prefix-list DEFAULT-ROUTE seq 5 permit 0.0.0.0/0
!
ip prefix-list PREPEND-LIST seq 5 permit AAA.AAA.AAA.0/24
logging trap debugging
access-list 30 deny 224.0.1.35 log
access-list 30 deny 224.0.1.60 log
access-list 30 deny 224.0.1.3 log
access-list 30 deny 224.0.1.2 log
access-list 30 deny 224.0.1.22 log
access-list 30 deny 224.0.1.24 log
access-list 30 remark Multicast Filtering ACL
access-list 30 deny 224.0.0.0 0.0.0.255 log
access-list 30 deny 239.0.0.0 0.255.255.255 log
access-list 30 permit 224.0.0.0 15.255.255.255 log
access-list 101 permit ip any any
!
route-map PREPEND-MAP-B permit 10
match ip address prefix-list PREPEND-LIST
set as-path prepend 123456 123456 123456 123456
!
route-map PREPEND-MAP-B permit 20
!
route-map DEFAULT-ONLY permit 10
match ip address prefix-list DEFAULT-ROUTE
02-27-2020 06:03 PM
Hi,
It seems with your configuration that you are advertizing, you can verify it with below command to see what has been advertized:
show ip bgp neighbor bbb.bbb.bbb.1 advertised-routes
03-02-2020 07:20 AM
Thank you for the reply.
I get the following results when issuing the show ip bgp neighbor bbb.bbb.bbb.1 advertised-routes command -
Network Next Hop Metric LocPrf Weight Path
*> AAA.AAA.AAA.0/25 0.0.0.0 0 32768 i
*> BBB.BBB.BBB.0/29 0.0.0.0 0 32768 i
Total number of prefixes 2
I'm surprised by the weight.
02-27-2020 07:49 PM
03-02-2020 07:26 AM
Thank you for the reply.
I get the following results when issuing the show ip bgp neighbor bbb.bbb.bbb.1 advertised-routes command -
Network Next Hop Metric LocPrf Weight Path
*> AAA.AAA.AAA.0/25 0.0.0.0 0 32768 i
*> BBB.BBB.BBB.0/29 0.0.0.0 0 32768 i
Total number of prefixes 2
I'm surprised by the weight.
What is the goal of my default route route-map? I am just trying to manipulate a configuration of my predecessor and would gladly simplify if I could. It's been years since I've had to do anything BGP even for classes and definitively out of practice.
The big difference and challenge for me with this one is that there is only one /24 range allotted to us by this provider. I've only worked with two separate /24 subnet ranges previously. So I'm sure the pre-pend is part of our problem here.
I've tried to divide it in half and use a /25 range on each circuit. Not sure how forgiving or specific the upstream neighbor will be.
03-02-2020 09:47 AM
I don’t think Cogent will accept a /25 and certainly not a /29.
Jon
03-02-2020 03:42 PM
You were right about the providor not accepting anything less than the full /24. Not sure how I'm supposed to configure the other circuit now.
03-02-2020 11:56 PM
It's not clear whether you only have one /24 for both circuits or a /24 from each provider ?
What exactly do you want to do with your addressing ?
Jon
03-02-2020 03:32 PM
03-03-2020 03:39 AM
03-03-2020 03:54 AM - edited 03-03-2020 04:47 AM
If you just want fault tolerance advertise /24 out of both circuits and AS prepend on one circuit so all traffic uses the other circuit unless it is unavailable.
Or advertise out /24 as is out of both and let the routing take care of it although you are more likely to get asymmetric traffic.
Jon
03-04-2020 02:50 PM
03-03-2020 03:22 PM
03-04-2020 02:49 PM
03-04-2020 06:36 PM
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