04-03-2009 12:34 PM - edited 03-06-2019 04:58 AM
I want to filter a redistributed static host route - /32 from being advertised through EIGRP to a neighboring router.
If I create an acces-list like this:
access-list 10 deny 10.l.1.1 0.0.0.0
access-list 10 permit any
Here is the static route:
ip route 10.1.1.1 255.255.255.255 10.2.1.1
ip route 10.2.1.1 255.255.255.0 10.20.100.0
Here is the routing proto:
router eigrp 1
redistribute static
distribute-list 10 out static
Only the 10.1.1.1 host route is filtered....and the second /24 gets through? Do distribute-lists normally filter redistributed static routes or just the networks listed under EIGRP?
Thank you!
04-03-2009 01:23 PM
Personally, I like using a route map attached to the redistribute statement.
route-map REDIS.STATIC deny 10
match ip address 10
route-map REDIS.STATIC permit 20
access-list 10 permit 10.1.1.1
router eigrp 1
redistribute static metric 1000000 10 255 1 1500 route-map REDIS.STATIC
ip route 10.1.1.1 255.255.255.255 10.2.1.1
ip route 10.2.1.1 255.255.255.0 10.20.100.0
10.1.1.1 gets redistributed, 10.2.1.1 does not.
HTH
Victor
04-03-2009 02:24 PM
It actually depends on the configuration
For eg..
distribute-list 10 out static will restrict the static routes to be redistributed (if redistribute static is configured) It still advertises the Prefixes that are learnt as a result of turning on EIGRP using network statements
on the other hand distribute-list 10 out will filter out everything being advertised from every interface
eg.. R1(e0/1) -- e0/0(R2)
R1
router eigrp 1
redistribute static
network 1.0.0.0
network 2.0.0.0
network 20.0.0.0
distribute-list 1 out static
distribute-list 1 out Ethernet0/0
no auto-summary
!
ip http server
ip classless
ip route 3.3.3.0 255.255.255.0 10.10.10.1
access-list 1 permit 1.1.1.1
r2
r2#sh ip route
Gateway of last resort is not set
1.0.0.0/24 is subnetted, 1 subnets
D 1.1.1.0 [90/409600] via 20.20.20.1, 00:01:50, Ethernet0/0
2.0.0.0/24 is subnetted, 1 subnets
D 2.2.2.0 [90/409600] via 20.20.20.1, 00:01:50, Ethernet0/0
20.0.0.0/24 is subnetted, 1 subnets
C 20.20.20.0 is directly connected, Ethernet0/0
r2#
As you see, eventhough the distribute-list is configured since it has a static keyword, only that prefix gets filtered.
Narayan
04-03-2009 02:43 PM
I tried filtering 6 static routes last night using an access-list, but did not use the "static" keyword and it did not appear to work. The neighbor router never dropped the route.Since this is a third-party managed router I could not clear the eigrp neighbor or route table to make it refresh. How long does it hold on to an advertised route and then drop based on not receiving it. My static routes were not listed under the EIGRP routing process. Did I not wait long enough for the route to drop out. I know my access-list was correct.
04-03-2009 02:49 PM
Actually the moment you change the configuration of the distribute-list, the router would send a good bye message and reestablish the adjacency so it is almost immediate
If you want to advertise only a set of static routes, you can use a route-map directly with redistribution as suggested by Victor
Narayan
04-03-2009 03:01 PM
You also didnt establish a seed metric in your config from last night.
Thats probably why it didnt work.
Did you notice that I added that?
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