Dear all

Right now, the senario as following:
Ip address 9.181.137.143
netmask 255.255.255.0
interface eth0
default gw 9.181.137.1

Next, I want to chang the IP address to another subnet mask like this:
ip adderss 9.27.22.244
netmask 255.255.252.0
interfce eth0

But when I run script "ifconfig " to modify the ip address, then the default route will lose because of the sumnetmask changed.

So my question is how to maintain the ssh connection while I want to change the default route in linux? Do you think it is possible to maintain it from the technique? That is urgent and thank you for any response or suggestion

I tried on a box a couple of possible solutions but they didn't work.
I think it isn't possible :/

With the new address you have no new gateway again? You will need one which you can reach locally.

Do you want to keep a session open or a tunnel? You can look into screen to reconnect a session and/or autossh tools.