Variable Subnet (I didn't do it!)

[mesagreg]

Hey Gang,
I have a 2621 router whose serial interface is configured as follows:


interface Serial0/0
bandwidth 1544
ip address 64.89.110.134 255.255.255.252
ip access-group 150 in
ip access-group 100 out
ip verify unicast reverse-path
no ip redirects
no ip unreachables
no ip directed-broadcast
no ip proxy-arp
ip nat outside
encapsulation ppp
no ip mroute-cache
no fair-queue
no cdp enable

When I issue a show ip route command, this is what I get:

Gateway of last resort is 64.89.110.133 to network 0.0.0.0

S 192.168.31.0/24 [1/0] via 192.168.20.1
S 192.168.30.0/24 [1/0] via 192.168.20.1
64.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C 64.89.110.133/32 is directly connected, Serial0/0
C 64.89.110.132/30 is directly connected, Serial0/0
S 192.168.42.0/24 [1/0] via 192.168.20.1
S 192.168.25.0/24 [1/0] via 192.168.20.1
S 192.168.43.0/24 [1/0] via 192.168.20.1
S 192.168.24.0/24 [1/0] via 192.168.20.1
S 192.168.40.0/24 [1/0] via 192.168.20.1
S 192.168.41.0/24 [1/0] via 192.168.20.1
S 128.1.0.0/16 [1/0] via 192.168.0.1
S 128.65.0.0/16 [1/0] via 192.168.50.2
S 192.168.21.0/24 [1/0] via 192.168.20.1
C 192.168.20.0/24 is directly connected, FastEthernet0/0
S 192.168.23.0/24 [1/0] via 192.168.20.1
S 192.168.22.0/24 [1/0] via 192.168.20.1
S 192.168.0.0/24 [1/0] via 192.168.20.1
192.168.50.0/30 is subnetted, 1 subnets
C 192.168.50.0 is directly connected, Serial0/1.1
S 192.168.32.0/24 [1/0] via 192.168.20.1
S* 0.0.0.0/0 [1/0] via 64.89.110.133

What's funny about this is the variable subnetting shown on Serial0/0. The 64.89.110.133/32 means it has a subnet mask of all ones!!! I can't figure this out. I have no other statements in my configuration that pertain to this network.

Do you think it's just one of those IOS "features" that requires an upgrade, or am I missing something here?

Thanks in advance,
Gregory A. Lusk, P.E., CCNA

 

[Jsteve]

I looks like someone typed in the wrong static ip address by mistake and never removed the statement.

try removing that sunbet address and see if it still shows up in your routing table.

routr(config)#int s0/0
routr(config-if)#no ip address 64.89.110.133 255.255.255.255

 

[mesagreg]

Actually, I typed "no ip address" and the entry was removed from the routing table. When I put it back in, however, it came back.

Gregory A. Lusk, P.E., CCNA

 

[Jsteve]

I see your using all static routes, do you have a routing protocol enabled?

 

[mesagreg]

I was in the process of setting up RIP v2 this afternoon and getting rid of the static routes wherever possible. I am going to finish it tomorrow. Gregory A. Lusk, P.E., CCNA

 

[wybnormal]

Just remember that RIP2 will automaticly summarize the VLSM. If you dont want it to do that, you need to type in the > no auto-summary

Many of us forget this and end up somewhat red in the face when it's pointed out :~/

Not that *I* would EVER do this.. :::clearing of one's throat:::

MikeS
Find me at

http://www.packetattack.com

"The trouble with giving up civil rights is that you never get them back"

 

[mesagreg]

Thanks, Mike. Do you have any insight on this problem? The router does not seem to be routing properly. I can ping hosts beyond it from certain subnets, but not from others. I'm pretty sure that I need to get rid of this all 1's subnet, but I'm not sure where it's coming from. Gregory A. Lusk, P.E., CCNA

 

[bierhunter]

Every router we have that has a serial connection shows the same thing. Also, it's a connected route, so it will appear by itself unlike a static route that has to be entered. I also always seems to be the address of the other end of the segment. The other router probably has one similar pointing back.

I really have no explaination for it. I've also not seen any problems arise because of it. I stopped looking into it a few years ago, since everything's working fine. Cisco's website may have some more indepth info.

 

[mesagreg]

I have a router with a very similar configuration that does not have this entry. We are also experiencing problems reaching the Internet from remote networks that are connected to this router. It looks like a routing issue, so my suspicion is that this may be related. Gregory A. Lusk, P.E., CCNA

 

[svermill]

Just commenting the /32 mask issue, this always occurs as a result of using ppp encapsulation. It is normal and expected. You can move on with finding your routing issue without regard to the /32 mask.

 

[mesagreg]

Okay. Thanks. We actually resolved the problem. It was due to misconfiguration of NAT.

Thanks for all the responses.

Gregory A. Lusk, P.E., CCNA

 

[Jsteve]

What was the misconfiguration?

 

[mesagreg]

I did not have IP NAT inside configured on the subinterface that connected to the remote network, and my NAT access list did not allow hosts from the remote network to obtain addresses.

The problem is always in the last place you look! Gregory A. Lusk, P.E., CCNA