[c-nsp] Cursed IP address

[Victor Sudakov]

Colleagues,

We have found a very interesting problem. 

There are a dozen routers connected to a common 10.65.127.224/27 L2
backbone. All are running OSPF area 0. Any router which has the IP
address 10.65.127.246 cannot establish OSPF adjacency with some other 
routers, showing them forever in the INIT/DROTHER or EXSTART/DROTHER
state.

When a different IP address is configured on the same router, the
problem is solved. More over, when 10.65.127.246 is configured on ANY
router in the segment, it experiences adjacency problems.

We are currently using a workaround of never assigning 10.65.127.246
to any router. Is this Sauron's IP address, or is there some kind of curse
thereon?

Below is a typical output 

sw-bptoik#sh ip ospf 12 neighbor

Neighbor ID     Pri   State           Dead Time   Address         Interface
10.65.127.7     130   2WAY/DROTHER    984 msec    10.65.127.249   Vlan22
10.65.127.9     130   FULL/DR         707 msec    10.65.127.250   Vlan22
10.65.127.10      1   2WAY/DROTHER    942 msec    10.65.127.248   Vlan22
10.65.127.12      1   2WAY/DROTHER    841 msec    10.65.127.252   Vlan22
10.65.127.13      1   INIT/DROTHER    942 msec    10.65.127.235   Vlan22
10.65.127.14      1   INIT/DROTHER    782 msec    10.65.127.245   Vlan22
10.65.127.15    130   INIT/DROTHER    908 msec    10.65.127.251   Vlan22
10.65.127.17      1   2WAY/DROTHER    866 msec    10.65.127.241   Vlan22
10.65.127.19      1   2WAY/DROTHER    959 msec    10.65.127.238   Vlan22
10.65.127.21      1   2WAY/DROTHER    740 msec    10.65.127.244   Vlan22
10.65.127.22      0   INIT/DROTHER    766 msec    10.65.127.243   Vlan22
10.65.127.23      1   2WAY/DROTHER    891 msec    10.65.127.230   Vlan22
10.65.127.24      1   2WAY/DROTHER    682 msec    10.65.127.231   Vlan22
10.65.155.11      1   2WAY/DROTHER    816 msec    10.65.127.253   Vlan22
172.16.146.11     1   2WAY/DROTHER    858 msec    10.65.127.247   Vlan22


sw-bptoik#sh ip ospf int Vlan22
Vlan22 is up, line protocol is up
  Internet Address 10.65.127.246/27, Area 0
  Process ID 12, Router ID 10.65.127.246, Network Type BROADCAST, Cost: 1
  Topology-MTID    Cost    Disabled    Shutdown      Topology Name
        0           1         no          no            Base
  Transmit Delay is 1 sec, State DROTHER, Priority 1
  Designated Router (ID) 10.65.127.9, Interface address 10.65.127.250
  Backup Designated router (ID) 10.65.127.9, Interface address 10.65.127.250
  Timer intervals configured, Hello 333 msec, Dead 1, Wait 1, Retransmit 5
    oob-resync timeout 40
    Hello due in 264 msec
  Supports Link-local Signaling (LLS)
  Cisco NSF helper support enabled
  IETF NSF helper support enabled
  Index 1/1, flood queue length 0
  Next 0x0(0)/0x0(0)
  Last flood scan length is 1, maximum is 1
  Last flood scan time is 0 msec, maximum is 0 msec
  Neighbor Count is 15, Adjacent neighbor count is 1
    Adjacent with neighbor 10.65.127.9  (Designated Router)
  Suppress hello for 0 neighbor(s)



-- 
Victor Sudakov,  VAS4-RIPE, VAS47-RIPN
sip:sudakov at sibptus.tomsk.ru