06-30-2008 05:55 PM - edited 03-03-2019 10:33 PM
Our current configurations for our lan are 2960 swithces that get their ip's from DHCP (not sure why our admin wanted it this way)
so the basic configurations are this
!
interface Vlan1
no ip address
no ip route-cache
shutdown
!
interface Vlan134
ip address dhcp
no ip route-cache
!
While I was away a consultant needed
to add a 2950 switch. Instead of following the standard configuration as you see above...he statically assigned
each vlan its own IP address...
He also didnt configure the port on the
2950 as a trunk, which would be attached
to the 2960. The 2960 gig port is a trunk
so i configured the 2950 port as a trunk..
He also mistakenly assigned all the ports
on the switch to the wrong vlan-133. So i
re configured them to the right vlan-134
However this was the configuration just before I lost access on the 2950
!
interface GigabitEthernet0/1
description Uplink to 2960 gig0/46
switchport mode trunk
no ip address
!
interface GigabitEthernet0/2
no ip address
!
interface Vlan1
no ip address
no ip route-cache
shutdown
!
interface Vlan133
ip address 192.168.133.182 255.255.255.0
no ip route-cache
!
interface Vlan134
ip address 192.168.134.182 255.255.254.0
no ip route-cache
shutdown
!
ip default-gateway 192.168.133.1
no ip http server
Since all the user ports were now on vlan 134, I needed to enable that particluar vlan since it was shut
cat7.2950#conf t
Enter configuration commands, one per line. End with CNTL/Z.
cat7.2950(config)#int vlan 134
cat7.2950(config-if)#no sh
Connection to host lost.
Now I cant access that 2950, however the cdp neighbor on the 2960 still shows the 2950..
cat6.2960#sh cdp ne det
Device ID: cat7.2950
Entry address(es):
IP address: 192.168.133.182
Platform: cisco WS-C2950T-24, Capabilities: Switch IGMP
I cant ping that 2950..any ideas?
also is the 2950 capable of getting its ip address from dhcp?
06-30-2008 06:11 PM
hmmm..
so i can access the router with the IP address of vlan 134 and vlan 133 is shut, which i did not shut
interface Vlan133
ip address 192.168.133.182 255.255.255.0
no ip route-cache
shutdown
!
interface Vlan134
ip address 192.168.134.182 255.255.254.0
no ip route-cache
and the cdp of the sister router is stil showing the 133 address...i even cleared
the cdp table of the sister router
cat6.2960#sh cdp ne det
Device ID: cat7.2950
Entry address(es):
IP address: 192.168.133.182
but the ip is still unpingable..prob cuz its shut!..but why is it in cdp?
06-30-2008 06:22 PM
Try to ping " cat7.2950" ? You haven't here put complete comfiguration, I think.
THanks,
Dharmesh
07-01-2008 04:48 AM
ok-it seems cdp has updated with the interface vlan 134 IP..and i can now access the
switch..
but why would the interface vlan 133 shut itself down?
07-02-2008 05:24 AM
Hi,
IMHO, 2950 is a L2 switch which can have only one IP address active on a management interface.
You can define more IP addresses assigned to particular "int VLAN x", but always all are shutdown except of one active.
If you issue "no shut" on another int VLANy, it automatically shuts the previous active management int VLAN x.
CDP remains advertising the original info for some time, it was even necessary to reload the switch to update CDP info sent with previous IOS versions :-(
BR,
Milan
07-02-2008 05:55 AM
Hello,
it is like Milan has explained : I've seen this behaviour when I did some security tests : as soon as you define a new SVI VLan with its own ip address the previous one is automatically shutted down
If you re-enable the first vlan it is the second one that is disabled and so on.
best regards
Giuseppe
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