# Reconfiguring multiplexer IP/UDP ports

This topic describes how to change the IP/UDP ports used by the NMS multiplexer after the master agent, the NMS multiplexer, and the subagents are running.

By default, the NMS multiplexer uses the following IP/UDP ports:

IP/UDP port | Value
--- | ---
Communication port between the NMS multiplexer and the network | 161
Communication port between the SNMP master agent and the NMS multiplexer | 49212
Communication port between the NMS SNMP subagents and the NMS multiplexer | 49213

These port values are stored in the snmp.cfg. To change the values, edit snmp.cfg by completing the following steps:

Step | Action
1 | Locate snmp.cfg in one of the following directories:
Operating system | Directory
--- | ---
Windows | \nms\ctaccess\cfg\
UNIX | /opt/nms/ctaccess/cfg/
2 | Modify the settings in the file.
3 | Save and close the file.
4 | To make the changes effective, restart the master agent, the NMS multiplexer, and the subagents.

For more information on the snmp.cfg file, see Configuring NMS SNMP.