UDP Port 177 – xdmcp

About UDP Port 177

Port 177 is registered with the Internet Assigned Numbers Authority (IANA) for xdmcp. The IANA description reads: ‘X Display Manager Control Protocol’. This port appears in 2 IDS rules and does not have notable malware activity indicators in our data.

IDS Rule References

2 IDS / security rules reference UDP port 177. Treat that number as context, not a danger score. Many detection rules are written against groups of ports rather than one service, web ports especially, so common web alternate ports inherit large counts while genuinely sensitive services can show few rules or none. Presence in IDS rules does not mean traffic on this port is malicious.

Rule categories (top 1): attempted-recon (2).

Sample rule descriptions for UDP port 177:

• X11 xdmcp query
• X11 xdmcp info query

Data Sources

This information is compiled from: IANA Service Name and Transport Protocol Port Number Registry and Snort Community Rules (GPLv2).