Hi there,
"I can't get the router to switch over because every time I try and change the internal IP, I get disconnected and can't get back to the router." If you're talking about the 5505, it is a firewall, not a router although it can do layer 3 functions like routing.
To do what you're asking, I'm going to assume that you are connecting to the 5505 via a terminal that IS ON THE SAME LAN as the internal interface of the 5505.
Get in like normal via ssh or telnet and tell the 5505 that you want to telnet or ssh into it from a new network.
telnet 192.168.0.0 255.255.255.0 inside <--- this tells the 5505 to allow telnet connections from the network 192.168.0.0/24 on the inside interface
ssh 192.168.0.0 255.255.255.0 inside <--- this tells the 5505 to allow ssh connections from the network 192.168.0.0/24 on the inside interface
Go into the relevant VLAN and change the IP address of the internal interface.. you will lose your connection; then change your IP address (on your management station/laptop or whatever you're using to get to the device) to be on the same network as the 5505's internal address.
Assuming there is no access-list on the inside interface, that should work.
If the terminal IS NOT ON THE SAME LAN then you'll need to update the default route so it's pointing to the new network's IP on the attached router.
Good luck with it!
Brad
