cisco 3550: assigning an ip to a loopback, but not able to ping it.
Posted on 2004-09-07
I'm having a problem (probably conceptual) with assigning an ip to a loopback address, and then pinging it.
There are six 3550 switches (without the routing addon). These switches are clustered, and there are 3 vlans on the cluster.
The six switches are hostnamed:
The vlans are LANA, LANB, and BIZ
vlan1 is LANA is 10.10.1.0/24
vlan2 is LANB is 10.10.2.0/24
vlan5 is BIZ is 192.168.1.0/24
The cluster master is LAN_A_S1, and has 10.10.1.111 assigned to vlan1. There are no other ips on the switches.
Altho we had intended to segregate LANA and LANB with the corresponding switches, it didn't turn out that way, so the LAN_A_x switches have machines on all the vlans on them, as do the LAN_B_x switches.
vlan1 is where most of the machines are at, and most of the traffic occurs.
There is no routing between the vlans.
I'm a CLI kinda guy, so following my usual practice, I went to assign ips to loopback0 on each of the switches as follows:
Now I go to my desktop machine (gentoo linux ip 10.10.1.176) to ping the LANA switches, and....nothing.
I can ping the LAN_A_S1 vlan1 ip (10.10.1.111), but not .1.112 or .1.113 or .1.114.
ditto for the 10.10.2.0 vlan from another machine (10.10.2.176).
Since I can ping the vlan1 ip, but not -any- of the loopbacks, I'm sure I'm missing/ forgetting something, but I don't know what. Any pointers welcome.
Another question is what the the subnet mask should be? I've used 255.255.255.0 for everything, but maybe on the loopbacks it should be 255.255.255.255? On the other hand, all the configs have no ip classless in them.....
Another question is...why was LAN_A_S1's ip assigned to the vlan, and not the loopback?
Thanks in advance!