Port 11211 is Memcached, TCP and UDP.
TCPUDP
high risk
App-IDmemcached
Memcached distributed cache — no authentication. UDP mode has been used for massive DDoS amplification attacks.
Palo Alto
Create the service objects for this port, then allow the App-ID on it. Restricting the rule to the port's service object keeps the rule working on a non-default port and stops the App-ID matching on other ports. Replace the placeholders with your own rule name and zones.
set service tcp-11211 protocol tcp port 11211
set service udp-11211 protocol udp port 11211
set rulebase security rules <rule-name> from <from-zone> to <to-zone> source any destination any application memcached service [ tcp-11211 udp-11211 ] action allow
Risk and exposure
Rated high risk. Services on this port are commonly targeted by attackers. Keep it off the internet, or put it behind a VPN or a strict source allow-list, and monitor access.
Check it
- Linux
ss -tlnp | grep :11211 - Linux
ss -ulnp | grep :11211 - PowerShell
Test-NetConnection <host> -Port 11211 - nmap
nmap -p 11211 <host> - nmap
nmap -sU -p 11211 <host>