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Port 5504 (fcp-cics-gw1)

IANA assigns port 5504 to fcp-cics-gw1.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
fcp-cics-gw1 TCP fcp-cics-gw1 Ken Wittmer -
fcp-cics-gw1 UDP fcp-cics-gw1 Ken Wittmer -

Check what is listening on port 5504

Linux: is anything listening on TCP 5504?
sudo ss -tlnp 'sport = :5504'
Linux: UDP 5504
sudo ss -ulnp 'sport = :5504'
Linux / macOS: which process owns the port
sudo lsof -nP -i :5504
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':5504 '
Windows (Command Prompt)
netstat -ano | findstr :5504
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 5504 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 5504
From Windows
Test-NetConnection HOST -Port 5504
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 5504

Block port 5504 in the firewall

ufw
sudo ufw deny 5504/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 5504 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 5504 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 5504' -Direction Inbound -Protocol TCP -LocalPort 5504 -Action Block
ufw
sudo ufw deny 5504/udp
iptables
sudo iptables -A INPUT -p udp --dport 5504 -j DROP
nftables
sudo nft add rule inet filter input udp dport 5504 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 5504' -Direction Inbound -Protocol UDP -LocalPort 5504 -Action Block

Related ports

5502fcp-srvr-inst15503fcp-srvr-inst25505checkoutdb5506amc

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