OSPF and Forcing a Subnet

Randy randy_94108 at yahoo.com
Sat Jul 20 20:51:37 UTC 2013


what you are seeing is the expected behavior.

you are asking the router to generate a type 3 summary for a type 1 lsa that doesn't exist for area 10 via the "area 10 range' command" (also, that is why it works when you add a /32 to loopback)

172.16/16 is an external route. If you want to generate a type 5 aggregate use summary-addr as Jon has pointed out. Else, leave static in place, redist static subnets but remove "area 10 range 172.16.0.0 255.255.0.0" from ospf config.
./Randy




_______________________________
> From: Shahab Vahabzadeh <sh.vahabzadeh at gmail.com>
>To: Jon Lewis <jlewis at lewis.org> 
>Cc: nanog <nanog at nanog.org> 
>Sent: Saturday, July 20, 2013 12:55 PM
>Subject: Re: OSPF and Forcing a Subnet
> 
>
>Dear Jon I have a mistake in my last email, there is a static route like
>this:
>
>ip route 172.16.0.0 255.255.0.0 10.20.76.12
>
>but again it is redistributing
>
>
>On Sun, Jul 21, 2013 at 12:22 AM, Jon Lewis <jlewis at lewis.org> wrote:
>
>> You don't have a route for 172.16/16 in the config below, so ospf will not
>> advertise it.  You do have a route for a subnet of 172.16/16, so either use
>> summary-address 172.16.0.0 255.255.0.0 or nail up a static route for
>> 172.16.0.0 255.255.0.0 to null0 and redistribute static subnets, and then
>> ospf can redistribute that static route.
>>
>>
>> On Sun, 21 Jul 2013, Shahab Vahabzadeh wrote:
>>
>>  Dear Friends,
>>> I have an OSPF over GRE configuration sending you below in which I have
>>> problem.
>>> I want to force OSPF to advertise 172.16/16 range without checking
>>> anything.
>>> And as you see I have an static route for it in routing table but again
>>> OSPF do not advertise it, only it advertise when I put one /32 subnet on
>>> loopback interface.
>>> even I put "redistribute static subnets" command with/without route-map
>>> but
>>> again do not work.
>>> I think because of having my providers address range in my static routes,
>>> routers and ospf confused when wanna advertise routers.
>>>
>>>
>>> interface Tunnel0
>>>
>>>>  ip address 128.140.40.2 255.255.255.252
>>>>  tunnel source 10.20.76.2
>>>>  tunnel destination 10.20.75.2
>>>> interface GigabitEthernet0/0
>>>>  description UPSTREAM - INTRANET
>>>>  ip address 10.20.76.2 255.255.255.248
>>>> interface GigabitEthernet0/1
>>>>  description CONNECTED ROUTER
>>>>  ip address 10.20.76.9 255.255.255.248
>>>>
>>>> router ospf 10
>>>>  log-adjacency-changes
>>>>  area 10 range 172.16.0.0 255.255.0.0
>>>>  passive-interface default
>>>>  no passive-interface Tunnel0
>>>>  network 172.16.0.0 0.0.255.255 area 10
>>>>  network 128.140.40.0 0.0.0.3 area 0
>>>> ip route 0.0.0.0 0.0.0.0 10.20.76.1
>>>> ip route 172.16.0.0 255.255.224.0 10.20.76.12
>>>> ip route 10.20.76.0 255.255.255.0 10.20.76.12
>>>> ip route 10.20.77.0 255.255.255.0 10.20.76.12
>>>>
>>>
>>>
>>>
>>> Thanks
>>>
>>> --
>>> Regards,
>>> Shahab Vahabzadeh, Network Engineer and System Administrator
>>>
>>> Cell Phone: +1 (415) 871 0742
>>> PGP Key Fingerprint = 8E34 B335 D702 0CA7 5A81  C2EE 76A2 46C2 5367 BF90
>>>
>>>
>> ------------------------------**------------------------------**----------
>>  Jon Lewis, MCP :)           |  I route
>>                              |  therefore you are
>> _________ http://www.lewis.org/~jlewis/**pgp<http://www.lewis.org/~jlewis/pgp>for PGP public key_________
>>
>
>
>
>-- 
>Regards,
>Shahab Vahabzadeh, Network Engineer and System Administrator
>
>Cell Phone: +1 (415) 871 0742
>PGP Key Fingerprint = 8E34 B335 D702 0CA7 5A81  C2EE 76A2 46C2 5367 BF90
>
>
>




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