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Port 163 (cmip-man)

IANA assigns port 163 to cmip-man: CMIP/TCP Manager.

Well-known (system) port, 0-1023 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
cmip-man TCP CMIP/TCP Manager - -
cmip-man UDP CMIP/TCP Manager - -

Check what is listening on port 163

Linux: is anything listening on TCP 163?
sudo ss -tlnp 'sport = :163'
Linux: UDP 163
sudo ss -ulnp 'sport = :163'
Linux / macOS: which process owns the port
sudo lsof -nP -i :163
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':163 '
Windows (Command Prompt)
netstat -ano | findstr :163
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 163 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 163
From Windows
Test-NetConnection HOST -Port 163
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 163

Block port 163 in the firewall

ufw
sudo ufw deny 163/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 163 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 163 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 163' -Direction Inbound -Protocol TCP -LocalPort 163 -Action Block
ufw
sudo ufw deny 163/udp
iptables
sudo iptables -A INPUT -p udp --dport 163 -j DROP
nftables
sudo nft add rule inet filter input udp dport 163 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 163' -Direction Inbound -Protocol UDP -LocalPort 163 -Action Block

Related ports

161SNMP162SNMP trap164cmip-agent165xns-courier

All port numbers · Open port checker
Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.