[c-nsp] Cursed IP address

[Harold 'Buz' Dale]

If you "sh arp" do you see the right MAC address for the ip. Could that address be in use on some dumb device? 

Sent from my iPhone

> On Nov 26, 2014, at 2:43, "Victor Sudakov" <vas at mpeks.tomsk.su> wrote:
> 
> 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
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