Hi!
Which static route, Can you post the output?
I will try to clarify:
If you have default route from neighbor 1.1.1.1 on you routing table before the filter. And you apply the prefix-list you posted before, what will happen then is: The default routing is out OFF the routing table but the default route is still on receiving table, you can check the command: "show ip bgp neighbors 1.1.1.1 received-routes" why? The neighbor 1.1.1.1 is still sending to you the default route but THE router you applied the prefix-list choose to block it.
Here is some show command on my test. I have two routers Router-A and Router-B. Router-A sending default routes to Router-B: the configuration off Router-B and the output without prefix-list:
conf:
router bgp 65000
bgp router-id 1.1.1.2
bgp log-neighbor-changes
network 50.50.50.0 mask 255.255.255.0
neighbor 1.1.1.1 remote-as 65000
neighbor 1.1.1.1 send-community
neighbor 1.1.1.1 soft-reconfiguration inbound
Router-B#show ip route bgp
Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
+ - replicated route, % - next hop override
Gateway of last resort is 1.1.1.1 to network 0.0.0.0
B* 0.0.0.0/0 [200/0] via 1.1.1.1, 00:02:00
40.0.0.0/24 is subnetted, 1 subnets
B 40.40.40.0 [200/0] via 1.1.1.1, 00:20:22
And now when you applied the prefix-list and did clear ip bgp * soft:
conf:
ip prefix-list no-default-route seq 5 deny 0.0.0.0/0
ip prefix-list no-default-route seq 10 permit 0.0.0.0/0 le 32
router bgp 65000
bgp router-id 1.1.1.2
bgp log-neighbor-changes
network 50.50.50.0 mask 255.255.255.0
neighbor 1.1.1.1 remote-as 65000
neighbor 1.1.1.1 send-community
neighbor 1.1.1.1 soft-reconfiguration inbound
neighbor 1.1.1.1 prefix-list no-default-route in
Router-B#show ip route bgp
Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
+ - replicated route, % - next hop override
Gateway of last resort is not set
40.0.0.0/24 is subnetted, 1 subnets
B 40.40.40.0 [200/0] via 1.1.1.1, 00:26:19
Now the default route is gone or out off the routing table, are you with me now?
Now when you run this command you will always see the default route why? the Router-A is still advertising to Router-B the default route, and Router-B uses prefix-list to block this routes, which means that you are not stopping the Router-A to advertise default router To Router-B, but Router-B only filter outs the default-routers which is coming from Router-A:
Router-B#show ip bgp neighbors 1.1.1.1 received-routes
BGP table version is 5, local router ID is 1.1.1.2
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
* i 0.0.0.0 1.1.1.1 0 100 0 ?
*>i 40.40.40.0/24 1.1.1.1 0 100 0 i
Total number of prefixes 2
Do you see the deference between when you have prefix now?
/Mohammed
