06-26-2009 03:59 AM - edited 03-06-2019 06:28 AM
Please can somebody explain what this route map is doing to the statics with tag 7?
Thank you in advance.
router ospf 1
router-id 172.103.11.113
log-adjacency-changes
redistribute static metric 1 subnets route-map OSPF_default
passive-interface default
no passive-interface Vlan2
no passive-interface FastEthernet1/0/1
no passive-interface FastEthernet2/0/1
network 172.25.0.0 0.0.255.255 area 0
network 172.27.0.0 0.0.255.255 area 0
network 172.30.0.0 0.0.255.255 area 0
network 172.103.11.0 0.0.0.127 area 0
network 172.103.18.0 0.0.0.255 area 0
!
ip classless
ip route 10.0.1.1 255.255.255.255 172.30.0.11 tag 7
ip route 10.0.1.10 255.255.255.255 172.30.0.11 tag 7
ip http server
!
!
access-list 5 permit X.X.X.0 0.0.0.255
access-list 5 permit X.239.34.0 0.0.0.255
access-list 5 permit X.239.35.0 0.0.0.255
access-list 5 permit X.102.6.0 0.0.0.255
access-list 5 permit X.102.7.0 0.0.0.255
access-list 5 permit X.102.8.0 0.0.0.255
access-list 5 permit X.102.9.0 0.0.0.255
access-list 5 permit X.30.0.0 0.0.255.255
access-list 6 deny any
access-list 7 deny any
access-list 8 permit any
access-list 144 permit ip X.X.X.0 0.0.0.255 172.103.0.0 0.0.255.255
access-list 144 permit ip X.X.X.0 0.0.0.255 172.103.0.0 0.0.255.255
route-map OSPF_default permit 7
match tag 7
!
Solved! Go to Solution.
07-14-2009 12:30 AM
'What does the permit 7 refer to if not the ACL?'
It is simply a list number used to order the lines in the route map. By default it is 10, 20, 30 and so on, but the person who had made the config ahs for some reason chosen the number 7 instead of the default 10.
HTH.
07-14-2009 03:05 AM
Carlton
It is a coincidence that there is an access list 7 and that the route map is matching 7. The access list 7 has no effect on the redistribution of static routes into OSPF. Without seeing more of the config we do not know what that access list is for, but it is not redistribution.
If you notice when the static routes are configured they are given a tag value:
ip route 10.0.1.1 255.255.255.255 172.30.0.11 tag 7
ip route 10.0.1.10 255.255.255.255 172.30.0.11 tag 7
and it is that tag value that the route map is matching against. So the result here is that there are 2 static routes configured and both of them will be redistributed. Perhaps it would clarify the issue if we consider the possibility of another static route being configured on this router. If the other static route looked like this:
ip route 192.168.51.0 255.255.255.0 172.30.0.11
Then there would be 3 static routes but only 2 of them would be redistributed.
There may be circumstances where you have multiple static routes configured and for policy reasons you want only some (but not all) of them to be advertised by the dynamic routing protocol like OSPF. Assigning some of the static routes a particular value of tag allows a route map to control redistribution and to select the correct static routes to be redistributed.
HTH
Rick
06-26-2009 04:04 AM
Hello Carlton,
only static routes with route tag=7 are redistributed into the OSPF domain
>> redistribute static metric 1 subnets route-map OSPF_default
you can check this with
sh ip ospf database external 10.0.1.1
sh ip ospf database external 10.0.1.10
or if you see advertised by OSPF in
sh ip route 10.0.1.1
Hope to help
Giuseppe
06-26-2009 04:41 AM
Thanks Guislar.
I was confused as to whether ACL 7 (Deny any)had anything to do with this route map?
I thought the permit 7 refered to the ACL of deny any and the match tag 7 refered to the route - therefore stopping the redistrubution.
What does the permit 7 refer to if not the ACL?
07-14-2009 12:30 AM
'What does the permit 7 refer to if not the ACL?'
It is simply a list number used to order the lines in the route map. By default it is 10, 20, 30 and so on, but the person who had made the config ahs for some reason chosen the number 7 instead of the default 10.
HTH.
07-14-2009 03:05 AM
Carlton
It is a coincidence that there is an access list 7 and that the route map is matching 7. The access list 7 has no effect on the redistribution of static routes into OSPF. Without seeing more of the config we do not know what that access list is for, but it is not redistribution.
If you notice when the static routes are configured they are given a tag value:
ip route 10.0.1.1 255.255.255.255 172.30.0.11 tag 7
ip route 10.0.1.10 255.255.255.255 172.30.0.11 tag 7
and it is that tag value that the route map is matching against. So the result here is that there are 2 static routes configured and both of them will be redistributed. Perhaps it would clarify the issue if we consider the possibility of another static route being configured on this router. If the other static route looked like this:
ip route 192.168.51.0 255.255.255.0 172.30.0.11
Then there would be 3 static routes but only 2 of them would be redistributed.
There may be circumstances where you have multiple static routes configured and for policy reasons you want only some (but not all) of them to be advertised by the dynamic routing protocol like OSPF. Assigning some of the static routes a particular value of tag allows a route map to control redistribution and to select the correct static routes to be redistributed.
HTH
Rick
07-14-2009 09:40 AM
Thank you both for clearing that up.
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