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Port 3211 (avsecuremgmt)

IANA assigns port 3211 to avsecuremgmt: Avocent Secure Management.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
avsecuremgmt TCP Avocent Secure Management Brian S Stewart -
avsecuremgmt UDP Avocent Secure Management Brian S Stewart -

Check what is listening on port 3211

Linux: is anything listening on TCP 3211?
sudo ss -tlnp 'sport = :3211'
Linux: UDP 3211
sudo ss -ulnp 'sport = :3211'
Linux / macOS: which process owns the port
sudo lsof -nP -i :3211
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':3211 '
Windows (Command Prompt)
netstat -ano | findstr :3211
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 3211 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 3211
From Windows
Test-NetConnection HOST -Port 3211
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 3211

Block port 3211 in the firewall

ufw
sudo ufw deny 3211/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 3211 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 3211 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 3211' -Direction Inbound -Protocol TCP -LocalPort 3211 -Action Block
ufw
sudo ufw deny 3211/udp
iptables
sudo iptables -A INPUT -p udp --dport 3211 -j DROP
nftables
sudo nft add rule inet filter input udp dport 3211 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 3211' -Direction Inbound -Protocol UDP -LocalPort 3211 -Action Block

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Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.