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Port 437 (comscm)

IANA assigns port 437 to comscm.

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

IANA assignment

Service nameProtoDescriptionAssigneeReference
comscm TCP comscm Jim Teague -
comscm UDP comscm Jim Teague -

Check what is listening on port 437

Linux: is anything listening on TCP 437?
sudo ss -tlnp 'sport = :437'
Linux: UDP 437
sudo ss -ulnp 'sport = :437'
Linux / macOS: which process owns the port
sudo lsof -nP -i :437
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':437 '
Windows (Command Prompt)
netstat -ano | findstr :437
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 437 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 437
From Windows
Test-NetConnection HOST -Port 437
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 437

Block port 437 in the firewall

ufw
sudo ufw deny 437/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 437 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 437 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 437' -Direction Inbound -Protocol TCP -LocalPort 437 -Action Block
ufw
sudo ufw deny 437/udp
iptables
sudo iptables -A INPUT -p udp --dport 437 -j DROP
nftables
sudo nft add rule inet filter input udp dport 437 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 437' -Direction Inbound -Protocol UDP -LocalPort 437 -Action Block

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