Changing a management IP in CatOS

[brian.bittner]

I have a client who is changing their management IP scheme as a bridge to replacing equipment and much of the old equipment (Catalyst 4000) is running CatOS and I am a bit weak in CatOS. The existing Management IP is setup as follows:

set interface sc0 1 192.168.252.209/255.255.255.0 192.168.252.255

set ip route 0.0.0.0/0.0.0.0         192.168.252.1

What we want to change this to is as follows:

set interface sc0 110 192.168.197.209/255.255.255.0 192.168.197.255

set ip route 0.0.0.0/0.0.0.0         192.168.197.1

The devices are spreadout over a large area and visiting each device is almost out of the question due to a time deadline I was wondering if I run this set of commands will this allow me to keep a remote session (SSH) running until the change is complete?

set ip route 192.168.197.0/255.255.255.0  192.168.197.1

set interface sc0 110 192.168.197.209/255.255.255.0 192.168.197.255

set ip route 0.0.0.0/0.0.0.0 192.168.197.1

Thanks in advance for all assistance!

[Giuseppe Larosa]

Hello Brian,

changes in CatOS are immediately operational and are saved in configuration!

as soon as you change the management interface ip address the SSH session will be unusable anymore.

So you should for each device:

open a first SSH session to current IP address

change the management IP address

open a new SSH session from a machine in new IP mgmt IP subnet 192.168.197.0 and configure the new static default route.

Ideally a workstation with two NICs one in old IP subnet and one in new IP subnet would be needed to do this (to run some form of script over it).

Have you got the console ports connected to a terminal server?  That would be the best way to do this kind of change as you would not risk to be locked out of the device.

Hope to help

Giuseppe

[brian.bittner]

Thanks for the info Giuseppe

In answer to your question, no we do not have the console port connected to a terminal server, I can go to each device physically and connect to the console port, but as I said due to the large area and time restrictions that is almost out of the question. So I am looking for a way to do this remotely, as I have about 90 devices to do. in your reply you said:

So you should for each device:

open a first SSH session to current IP address

change the management IP address

open a new SSH session from a machine in new IP mgmt IP subnet 192.168.197.0 and configure the new static default route.

If I change the IP, without changing the default route, then I won't be able to connect to the new IP until I change the route. So that would force me to go to each device.

What if I set a second route as I mentioned in the original question will that give me a temp way to access the device via the new so I can change the default route?

[Giuseppe Larosa]

Hello Brian,

an host with two NICs one in old IP subnet and one in new IP subnet is the ideal device for the job as it will be able to connect to new address even before the new default static route is configured

May be this a possible solution for you?

The host may be the default gateway of the management IP subnet for example I guess you are going to use secondary IP address on it to have  two different IP subnets supported on the same interface, or the new default gateway is a different device?

You can use an IOS router as the host using

interface fas0/0

ip address 192.168.197.x 255.255.255.0

ip address 192.168.252.x 255.255.255.0 secondary

!

a device like this can connect to old and new IP subnet without the need of static routes on the CATOS  side.

note:

you should try to check if the secondary option is available also in CatOS it might be.

Hope to help

Giuseppe

[glen.grant]

  You should be able to change the management address with your set SC0 command.  This will kill your session.  Just login into the device that is doing the routing  for that management space and just ssh back into the device . You should be able to get into the device even with the default gateway being in a different subnet because you are directly attached , then just change the default gateway to the new address.  Have done this many times.

     Your other option would be if you have all the current configs on a tftpserver  then just load the modified config file into bootflash and use the "set boot autoconfig command to load the new config file that is in bootflash. This method will require a reload of the box. 

    Also make sure you create vlan 110 on the new box and allow it on the trunks "FIRST" before changing the address otherwise you are going to isolate the box and a roadtrip will be in order.

[thomaslueder]

Hi there,

It would be also an option to NAT in your new management LAN.

NAT your workstation IP (or the whole Segment) behind the Layer 3 Interface of the new management LAN and you are able to connect regardless of the default gateway.

Greetings Thomas

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