From: Bit Gossip (bit.gossip@chello.nl)
Date: Tue Jun 19 2007 - 14:16:43 ART
Daniel,
I have labbed it and I get your exact same results:
the distribute-list not only prevents 2.2.2.2 to be installed in the RT but
also removes it from the database.
I have no idea why and is certainly in contrast to my undertanding of
distribute-list in OSPF
Thanks,
Bit.
----- Original Message -----
From: "Narbik Kocharians" <narbikk@gmail.com>
To: "Daniel Kutchin" <daniel@kutchin.com>
Cc: <ccielab@groupstudy.com>
Sent: Tuesday, June 12, 2007 12:32 AM
Subject: Re: Distribute-list & OSPF LSA 3
> Sorry for a delayed response, i was in the middle of some work, but I
> think
> the problem is with the ip prefix-list that you have configured, you
> forgot
> to assign sequence numbers, but here is what i got:
>
> *This is before the prefix-list / distribute-list*
> R1#Sh ip route ospf
> 2.0.0.0/32 is subnetted, 1 subnets
> O IA 2.2.2.2 [110/2] via 172.16.1.2, 00:03:21, FastEthernet0/0
> 3.0.0.0/32 is subnetted, 1 subnets
> O 3.3.3.3 [110/2] via 172.16.1.2, 00:03:21, FastEthernet0/0
> 4.0.0.0/32 is subnetted, 1 subnets
> O IA 4.4.4.4 [110/2] via 172.16.1.2, 00:03:21, FastEthernet0/0
>
> *R1#sh ip ospf da rou adv-router 4.4.4.4*
>
> OSPF Router with ID (172.16.2.1) (Process ID 1
>
> Router Link States (Area 0)
>
> Routing Bit Set on this LSA
> LS age: 239
> Options: (No TOS-capability, DC)
> LS Type: Router Links
> Link State ID: 4.4.4.4
> Advertising Router: 4.4.4.4
> LS Seq Number: 80000004
> Checksum: 0x2F44
> Length: 48
> Area Border Router
> Number of Links: 2
>
> Link connected to: a Stub Network
> (Link ID) Network/subnet number: 3.3.3.3
> (Link Data) Network Mask: 255.255.255.255
> Number of TOS metrics: 0
> TOS 0 Metrics: 1
>
> Link connected to: a Transit Network
> (Link ID) Designated Router address: 172.16.1.1
> (Link Data) Router Interface address: 172.16.1.2
> Number of TOS metrics: 0
> TOS 0 Metrics: 1
>
> *R1#sh ip ospf da summ adv-router 4.4.4.4*
>
> OSPF Router with ID (172.16.2.1) (Process ID 1)
>
> Summary Net Link States (Area 0)
>
> Routing Bit Set on this LSA
> LS age: 293
> Options: (No TOS-capability, DC, Upward)
> LS Type: Summary Links(Network)
> Link State ID: 2.2.2.2 (summary Network Number)
> Advertising Router: 4.4.4.4
> LS Seq Number: 80000001
> Checksum: 0xBE65
> Length: 28
> Network Mask: /32
> TOS: 0 Metric: 1
>
> Routing Bit Set on this LSA
> LS age: 283
> Options: (No TOS-capability, DC, Upward)
> LS Type: Summary Links(Network)
> Link State ID: 4.4.4.4 (summary Network Number)
> Advertising Router: 4.4.4.4
> LS Seq Number: 80000001
> Checksum: 0x62B9
> Length: 28
> Network Mask: /32
> TOS: 0 Metric: 1
>
>
> *R1(config)#ip prefix-list BLOCK seq 5 deny 2.2.2.2/32
> R1(config)#ip prefix-list BLOCK seq 10 deny 3.3.3.3/32
> R1(config)#ip prefix-list BLOCK seq 15 permit 0.0.0.0/0 le 32
> R1(config)#router ospf 1
> R1(config-router)#distribute-list prefix BLOCK in*
>
>
> *R1#sh ip rou ospf*
> 4.0.0.0/32 is subnetted, 1 subnets
> O IA 4.4.4.4 [110/2] via 172.16.1.2, 00:00:07, FastEthernet0/0
>
>
>
> *Note it did NOT effect the database*
>
> *R1#sh ip ospf da rou adv-router 4.4.4.4*
>
> OSPF Router with ID (172.16.2.1) (Process ID 1)
>
> Router Link States (Area 0)
>
> Routing Bit Set on this LSA
> LS age: 54
> Options: (No TOS-capability, DC)
> LS Type: Router Links
> Link State ID: 4.4.4.4
> Advertising Router: 4.4.4.4
> LS Seq Number: 80000006
> Checksum: 0x412F
> Length: 48
> Area Border Router
> Number of Links: 2
>
> Link connected to: a Stub Network
> (Link ID) Network/subnet number: 3.3.3.3
> (Link Data) Network Mask: 255.255.255.255
> Number of TOS metrics: 0
> TOS 0 Metrics: 1
>
> Link connected to: a Transit Network
> (Link ID) Designated Router address: 172.16.1.2
> (Link Data) Router Interface address: 172.16.1.2
> Number of TOS metrics: 0
> TOS 0 Metrics: 1
>
>
> *R1#sh ip ospf da summ adv-router 4.4.4.4*
>
> OSPF Router with ID (172.16.2.1) (Process ID 1)
>
> Summary Net Link States (Area 0)
>
> Routing Bit Set on this LSA
> LS age: 547
> Options: (No TOS-capability, DC, Upward)
> LS Type: Summary Links(Network)
> Link State ID: 2.2.2.2 (summary Network Number)
> Advertising Router: 4.4.4.4
> LS Seq Number: 80000001
> Checksum: 0xBE65
> Length: 28
> Network Mask: /32
> TOS: 0 Metric: 1
>
> Routing Bit Set on this LSA
> LS age: 537
> Options: (No TOS-capability, DC, Upward)
> LS Type: Summary Links(Network)
> Link State ID: 4.4.4.4 (summary Network Number)
> Advertising Router: 4.4.4.4
> LS Seq Number: 80000001
> Checksum: 0x62B9
> Length: 28
> Network Mask: /32
> TOS: 0 Metric: 1
>
>
>
>
>
> On 6/11/07, Daniel Kutchin <daniel@kutchin.com> wrote:
>>
>> Narbik ---
>>
>> This is exactly the problem here. Why is the database different when he
>> applies the filter?
>> And why only the Inter-Area prefix is filtered?
>>
>> #--- before:
>>
>> Summary Net Link States (Area 1)
>>
>> Link ID ADV Router Age Seq# Checksum
>> 2.2.2.2 1.1.1.1 2 0x80000001 0x007DA8 <---
>> will
>> be filtered
>> 3.3.3.3 1.1.1.1 2 0x80000001 0x004FD2 <---
>> will
>> be filtered
>> 4.4.4.4 1.1.1.1 2 0x80000001 0x0021FC
>> 172.16.1.0 1.1.1.1 3602 0x80000002 0x0056CA
>>
>>
>> #--- after:
>>
>> Summary Net Link States (Area 1)
>>
>> Link ID ADV Router Age Seq# Checksum
>> 3.3.3.3 1.1.1.1 574 0x80000001 0x004FD2 <---
>> only
>> this remains
>> 4.4.4.4 1.1.1.1 574 0x80000001 0x0021FC
>> 172.16.1.0 1.1.1.1 568 0x80000003 0x00B85D
>>
>>
>> -----Original Message-----
>> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
>> Narbik Kocharians
>> Sent: Montag, 11. Juni 2007 22:38
>> To: want2bccie@gmail.com
>> Cc: ccielab@groupstudy.com
>> Subject: Re: Distribute-list & OSPF LSA 3
>>
>> When you block prefixes using the "distribute-list in" command, the
>> prefixes
>> are filtered from the routing table BUT NOT the database.
>>
>> On 6/8/07, want2bccie@gmail.com <want2bccie@gmail.com> wrote:
>> >
>> > Hi GS,
>> >
>> > Below is my ospf topology
>> >
>> > Lo 3(3.3.3.3/32)__
>> > \ ___Lo 2(2.2.2.2/32)
>> > +----+ +----+ /
>> > Lo 1(1.1.1.1/32)--| R1 | | R2 |--X
>> > +----+ +----+ \___Lo 4(4.4.4.4/32)
>> > |fa0/0 fa0/0|
>> > | |
>> > |--172.16.1.0/30---|
>> >
>> > My config:
>> >
>> > -----------R1------------------------
>> > interface FastEthernet1/0
>> > ip address 172.16.1.1 255.255.255.0
>> > !
>> > interface Loopback1
>> > ip address 1.1.1.1 255.255.255.255
>> > !
>> > router ospf 1
>> > router-id 1.1.1.1
>> > log-adjacency-changes
>> > network 1.1.1.1 0.0.0.0 area 1
>> > network 172.16.1.1 0.0.0.0 area 0
>> > distribute-list prefix BLOCK in
>> > !
>> > ip prefix-list BLOCK seq deny 2.2.2.2/32
>> > ip prefix-list BLOCK seq deny 3.3.3.3/32
>> > ip prefix-list BLOCK seq permit 0.0.0.0/0 le 32
>> >
>> > --------------R2-----------------------
>> > interface FastEthernet1/0
>> > ip address 172.16.1.2 255.255.255.0
>> > !
>> > interface Loopback2
>> > ip address 2.2.2.2 255.255.255.255
>> > !
>> > interface Loopback3
>> > ip address 3.3.3.3 255.255.255.255
>> > !
>> > interface Loopback4
>> > ip address 4.4.4.4 255.255.255.255
>> > !
>> > router ospf 1
>> > router-id 2.2.2.2
>> > log-adjacency-changes
>> > network 2.2.2.2 0.0.0.0 area 2
>> > network 3.3.3.3 0.0.0.0 area 0
>> > network 4.4.4.4 0.0.0.0 area 4
>> > network 172.16.1.2 0.0.0.0 area 0
>> > ---------------------------------------
>> > R1#show ip ospf database
>> >
>> > OSPF Router with ID (1.1.1.1) (Process ID 1)
>> >
>> > Router Link States (Area 0)
>> >
>> >
>> > Link ID ADV Router Age Seq# Checksum Link
>> count
>> > 1.1.1.1 1.1.1.1 951 0x800000A5 0x8F6F 1
>> > 2.2.2.2 2.2.2.2 947 0x80000030 0x7ECF 2
>> >
>> >
>> > Net Link States (Area 0)
>> >
>> >
>> > Link ID ADV Router Age Seq# Checksum
>> > 172.16.1.1 1.1.1.1 954 0x80000001 0x6DFD
>> >
>> >
>> > Summary Net Link States (Area 0)
>> >
>> >
>> > Link ID ADV Router Age Seq# Checksum
>> > 1.1.1.1 1.1.1.1 1172 0x80000033 0xE21F
>> > 2.2.2.2 2.2.2.2 945 0x80000049 0x6A79
>> > 4.4.4.4 2.2.2.2 948 0x80000001 0x9E85
>> >
>> >
>> > Router Link States (Area 1)
>> >
>> >
>> > Link ID ADV Router Age Seq# Checksum Link
>> count
>> > 1.1.1.1 1.1.1.1 1184 0x80000001 0xD351 1
>> >
>> >
>> > Summary Net Link States (Area 1)
>> >
>> >
>> > Link ID ADV Router Age Seq# Checksum
>> > 3.3.3.3 1.1.1.1 946 0x80000001 0x4FD2
>> > 4.4.4.4 1.1.1.1 946 0x80000001 0x21FC
>> > 172.16.1.0 1.1.1.1 950 0x80000003 0x3B34
>> > ------------------------------------------------------------
>> >
>> > As per above config, on R1 OSPF learned routes should not installed in
>> its
>> > routing table but those routes still be in database and advertise to
>> > its
>> > neighbors. But in this case R1 is not getting type-3 LSA's for
>> 2.2.2.2network into ospf AREA 1.
>> > If above database output is correct, then can someone clear why R1
>> > won't
>> > get LSA3 for 2.2.2.2.
>> >
>> > Regards,
>> > Naresh
>> >
>> > _______________________________________________________________________
>> > Subscription information may be found at:
>> > http://www.groupstudy.com/list/CCIELab.html
>> >
>>
>>
>>
>> --
>> Narbik Kocharians
>> CCIE# 12410 (R&S, SP, Security)
>> CCSI# 30832
>> Network Learning, Inc. (CCIE class Instructor)
>> www.ccbootcamp.com (CCIE Training)
>>
>> _______________________________________________________________________
>> Subscription information may be found at:
>> http://www.groupstudy.com/list/CCIELab.html
>>
>> _______________________________________________________________________
>> Subscription information may be found at:
>> http://www.groupstudy.com/list/CCIELab.html
>>
>
>
>
> --
> Narbik Kocharians
> CCIE# 12410 (R&S, SP, Security)
> CCSI# 30832
> Network Learning, Inc. (CCIE class Instructor)
> www.ccbootcamp.com (CCIE Training)
>
> _______________________________________________________________________
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html
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