HTTPfy

Port 538 (gdomap)

IANA assigns port 538 to gdomap.

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

IANA assignment

Service nameProtoDescriptionAssigneeReference
gdomap TCP gdomap Richard Frith Macdon -
gdomap UDP gdomap Richard Frith Macdon -

Check what is listening on port 538

Linux: is anything listening on TCP 538?
sudo ss -tlnp 'sport = :538'
Linux: UDP 538
sudo ss -ulnp 'sport = :538'
Linux / macOS: which process owns the port
sudo lsof -nP -i :538
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':538 '
Windows (Command Prompt)
netstat -ano | findstr :538
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 538 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 538
From Windows
Test-NetConnection HOST -Port 538
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 538

Block port 538 in the firewall

ufw
sudo ufw deny 538/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 538 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 538 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 538' -Direction Inbound -Protocol TCP -LocalPort 538 -Action Block
ufw
sudo ufw deny 538/udp
iptables
sudo iptables -A INPUT -p udp --dport 538 -j DROP
nftables
sudo nft add rule inet filter input udp dport 538 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 538' -Direction Inbound -Protocol UDP -LocalPort 538 -Action Block

Related ports

536opalis-rdv537nmsp539apertus-ldp540uucp

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