If you connect a monitor, keyboard and mouse, the IP Address of an AppSrvCE can be changed the same way the IP is changed in a windows PC, going to the Control Panel -> Network Properties.
Tipically when an AppSrvCE is installed is not easy to connect a keyboard and monitor, so an alternate method is provided.
First is required to go online with the AppSrvCE via Telnet. To do this, you have to go to a DOS command prompt in any PC on the network and type this command:
where xxx.yyy.zzz.www is the IP address of the AppSrvCE. Once the Telnet connection is open you will get a dos prompt and there you have to type the command TCU. This command will open the AppSrvCE configuration utility which allows you to configure the network and security settings.
If after invoking the TCU utility you get a message:
*** Warning the registry is currently locked ***
that means that the configuration changes you make are not going to be saved. In order to be able to save configuration registers you first have to unlock the registry (option 3 of the TCU). This option requires to reboot the AppSrvCE.