TCP Port 51820

About TCP Port 51820

Port 51820 is not assigned to any service in the IANA Service Names and Port Numbers Registry. This port falls within the dynamic/private port range, which IANA explicitly does not register; these ports are intended for ephemeral or temporary use. It is referenced in 1 IDS rule but does not exhibit malware activity indicators in our data.

IDS Rule References

1 IDS / security rule reference TCP port 51820. 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-admin (1).

Sample rule descriptions for TCP port 51820:

• ET EXPLOIT Possible Apache log4j RCE Attempt – 2021/12/12 Obfuscation Observed M2 (udp) (CVE-2021-44228)

Data Sources

This information is compiled from: Emerging Threats Open Ruleset (BSD 2-Clause / GPLv2 per SID range).