(OSPF) some connected networks not distributed as such

[Ondrej Filip]

On Thu, 23 May 2002, Pim van Riezen wrote:

> Good Day,
> 
> This may be a cause of my newfound ignorance on the subject of OSPF
> routing, but it has had me boggled for a good part of the last two days. I
> have a linux 2.4 machine running bird on a non-broadcast connection to a
> Cisco 1600. The linux machine has the following configuration:

Hello,
please could you send me:

'show ospf'
'show ospf neighbor'
'show ospf interface'
etc..

				F.



> 
> ----- (interface connected to area 0) ----------------------------------
> eth0      Link encap:Ethernet  HWaddr 00:60:97:C2:36:47
>           inet addr:213.196.8.130  Bcast:213.196.8.135 Mask:255.255.255.248
>           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
> 
> ----- (interface that is the target of exchanged routes) ---------------
> eth2      Link encap:Ethernet  HWaddr 00:50:04:02:3B:91
>           inet addr:192.168.1.1  Bcast:192.168.1.255  Mask:255.255.255.0
> eth2:0    Link encap:Ethernet  HWaddr 00:50:04:02:3B:91
>           inet addr:202.36.147.1  Bcast:202.36.147.255  Mask:255.255.255.0
> eth2:1    Link encap:Ethernet  HWaddr 00:50:04:02:3B:91
>           inet addr:202.36.148.1  Bcast:202.36.148.255  Mask:255.255.255.0
> eth2:2    Link encap:Ethernet  HWaddr 00:50:04:02:3B:91
>           inet addr:202.50.64.1  Bcast:202.50.71.255  Mask:255.255.248.0
> 
> ----- (bird configuration on the machine) ------------------------------
> router id 213.196.8.130;
> filter outroute_filter {
>         if net ~ 213.196.8.136/29 then accept;
>         if net ~ 202.36.147.0/24 then accept;
>         if net ~ 202.36.148.0/24 then accept;
>         if net ~ 202.50.64.0/21 then accept;
>         else reject;
> };
> protocol static {
>         preference 1;
>         route 202.36.147.0:255.255.255.0 via "eth2";
>         route 202.36.148.0:255.255.255.0 via "eth2";
>         route 202.50.64.0:255.255.248.0 via "eth2";
> }
> protocol ospf MyOSPF {
>         area 0 {
>                 tick 1;
>                 interface "eth1" {
>                         type nonbroadcast;
>                         stub yes;
>                 };
>                 interface "eth0" {
>                         hello 30;
>                         retransmit 5;
>                         cost 10;
>                         type nonbroadcast;
>                         authentication none;
>                         neighbors {
>                                 213.196.8.133 eligible;
>                         };
>                         strict nonbroadcast yes;
>                 };
>                 interface "eth2" {
>                         cost 5;
>                         type nonbroadcast;
>                 };
>                 interface "eth2:0" {
>                         cost 5;
>                         type nonbroadcast;
>                 };
>                 interface "eth2:1" {
>                         cost 5;
>                         type nonbroadcast;
>                 };
>                 interface "eth2:2" {
>                         cost 5;
>                         type nonbroadcast;
>                 };
>                 interface "*" {
>                         stub yes;
>                 };
>         };
>         import filter { reject; };
>         export filter outroute_filter;
> };
> 
> -----( cisco configuration )------------------------------------------
> interface Ethernet0
>  description vlan2
>  ip address 213.196.8.133 255.255.255.248
>  ip access-group 101 out
>  no ip redirects
>  ip nat inside
>  ip ospf network non-broadcast
> !
> router ospf 31338
>  network 202.36.147.0 0.0.0.255 area 6
>  network 202.36.148.0 0.0.0.255 area 6
>  network 202.50.64.0 0.0.7.255 area 6
>  neighbor 213.196.8.131 priority 1
>  neighbor 213.196.8.130 priority 1
> !
> 
> -----------( the problem )----------------------------------------------
> gw-vlan2#sho ip route ospf
> O E2 202.36.148.0/24 [110/10000] via 213.196.8.130, 00:00:25, Ethernet0
> O    202.36.147.0/24 [110/15] via 213.196.8.130, 00:00:25, Ethernet0
> O E2 202.50.64.0/21 [110/10000] via 213.196.8.130, 00:00:25, Ethernet0
> gw-vlan2# sho ip ospf database router 213.196.8.130
> 
>        OSPF Router with ID (213.196.8.133) (Process ID 31338)
> 
> 
>                 Router Link States (Area 0)
> 
>   Routing Bit Set on this LSA
>   LS age: 399
>   Options: (No TOS-capability, No DC)
>   LS Type: Router Links
>   Link State ID: 213.196.8.130
>   Advertising Router: 213.196.8.130
>   LS Seq Number: 80000002
>   Checksum: 0x6342
>   Length: 72
>   AS Boundary Router
>    Number of Links: 2
> 
>     Link connected to: a Transit Network
>      (Link ID) Designated Router address: 213.196.8.130
>      (Link Data) Router Interface address: 213.196.8.130
>       Number of TOS metrics: 0
>        TOS 0 Metrics: 10
>     Link connected to: a Stub Network
>      (Link ID) Network/subnet number: 202.36.147.0
>      (Link Data) Network Mask: 255.255.255.0
>       Number of TOS metrics: 0
>        TOS 0 Metrics: 5
> 
> 
> 
> So... Which of the two (cisco or bird) made the decision that somehow
> 202.36.147.0/24 is a connected link whereas 202.36.148.0/24 is an external
> route, even though it is connected to the same interface? My head is
> hurting :)
> 
> Cheers,
> Pi
> 
> 

-- 
 (  IPEX a.s.   /   GIN internet communications  )
 -------------------------------------------------
  Ondrej Filip       Member of Board of Directors
 
  Office : Siroka 37,  Ceske Budejovice,    37001 
  Tel.   : +420-38-635 75 94    +420-38-635 76 23
  Email  : ondrej.filip at gin.cz  http://www.gin.cz     
 -------------------------------------------------