changing ISP and Tunnel is down

[nattesc82]

I am changing ISP and my ISP use 192.168.1. When I change the GigabitEthernet0/0 IP address that previously 192.168.0.254 into 192.168.1.254 the connection into hub is gone and now we are disconnected from VPN. any advice how this could happened and how to fix this?

[M02@rt37]

Hello @nattesc82 

You are not in DHCP on interface facing ISP ?

If no, do you have change the next hop of your default-route or of any static routes ?

[nattesc82]

No DHCP. I only change the interface IP address facing the ISP and access list

[M02@rt37]

OK, and what about routing ? The next-hop have changed...

[nattesc82]

no change. I just change the ip from ISP back into 192.168.0 and it's working again. but if I change into 192.168.1/2 it fails again

[balaji.bandi]

This required more information.

1. What device is used, and what is the iOS code running?

2. Is the IP LAN side or WAN side?

3. If this LAN side, ensure the other side matches the same subnet for the VPN to work.

4. What are the logs on the device that indicate why the tunnel is down?

5. show run configuration will help here (removing confidential information)

[nattesc82]

1. Cisco IOS Software, C1900 Software (C1900-UNIVERSALK9-M), Version 15.7(3)M9, RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2021 by Cisco Systems, Inc.
Compiled Tue 07-Sep-21 06:46 by mcpre

2. WAN side. IP that is facing the ISP GigabitEthernet0/0

3. Not sure about this

[nattesc82]

4. 

[nattesc82]

5. 

[balaji.bandi]

This information helps a little, but does not help how you connect the other side.

The IP is RFC 1918 IP address, and you are using DMVPN. Do you have access on the other side? (Make sure you also need to change the IP on the other side, from 192.168.0.0 to 192.168.1.0 network.

Can you post gig 0/0 config and tunnel interface config

[nattesc82]

Gig 0/0 this working one after change to 192.168.0

[nattesc82]

Tunnel config

[balaji.bandi]

is this Internet Link or MPLS ?

After changing the IP do you have internet access from router ?

see the mapping ip are you able to ping that IP ?

[nattesc82]

It was strange that I still got the internet and can ping public 202.90.245.136 but the next hop was disconnected the private 172.16.1.254

[balaji.bandi]

Do you have other side access where the hub ? can you able to post the configuration ? that is mapped ip - check the logs other side.