Port 5501 (fcp-addr-srvr2)

IANA assigns port 5501 to fcp-addr-srvr2.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference

fcp-addr-srvr2 TCP fcp-addr-srvr2 Ken Wittmer -

fcp-addr-srvr2 UDP fcp-addr-srvr2 Ken Wittmer -

Linux: is anything listening on TCP 5501?

sudo ss -tlnp 'sport = :5501'

Linux: UDP 5501

sudo ss -ulnp 'sport = :5501'

Linux / macOS: which process owns the port

sudo lsof -nP -i :5501

Older Linux / BSD (net-tools)

sudo netstat -tlnp | grep ':5501 '

Windows (Command Prompt)

netstat -ano | findstr :5501

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 5501 -State Listen | Select LocalAddress,OwningProcess

From another machine

nc -vz -w 5 HOST 5501

From Windows

Test-NetConnection HOST -Port 5501

UDP probe (no reply does not prove it is closed)

nc -vzu -w 5 HOST 5501

ufw

sudo ufw deny 5501/tcp

iptables

sudo iptables -A INPUT -p tcp --dport 5501 -j DROP

nftables

sudo nft add rule inet filter input tcp dport 5501 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block TCP 5501' -Direction Inbound -Protocol TCP -LocalPort 5501 -Action Block

ufw

sudo ufw deny 5501/udp

iptables

sudo iptables -A INPUT -p udp --dport 5501 -j DROP

nftables

sudo nft add rule inet filter input udp dport 5501 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'Block UDP 5501' -Direction Inbound -Protocol UDP -LocalPort 5501 -Action Block

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