By default, SNMPc uses TCP ports 165 through 168 in order to communicate with remote pollers and consoles. These ports can be changed by editing the SNMPC.INI file and modifying the port entries in the SNMPcConfig part. But make sure that you set the same values on both the server and remote computers.

If you are using the java console, you will have to allow port 12421 [and 31415 for remote telnet]. The SNMP protocol itself uses UDP port 161 for requests to a device and 162 for traps sent from the device to the manager.