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Port 8502 (ftnmtp)

IANA assigns port 8502 to ftnmtp: FTN Message Transfer Protocol.

Registered (user) port, 1024-49151 TCP

IANA assignment

Service nameProtoDescriptionAssigneeReference
ftnmtp TCP FTN Message Transfer Protocol Yuri Myakotin -

Registry dates for this port: registered 2014-01-07.

Check what is listening on port 8502

Linux: is anything listening on TCP 8502?
sudo ss -tlnp 'sport = :8502'
Linux / macOS: which process owns the port
sudo lsof -nP -i :8502
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':8502 '
Windows (Command Prompt)
netstat -ano | findstr :8502
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 8502 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 8502
From Windows
Test-NetConnection HOST -Port 8502

Block port 8502 in the firewall

ufw
sudo ufw deny 8502/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 8502 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 8502 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 8502' -Direction Inbound -Protocol TCP -LocalPort 8502 -Action Block

Related ports

8500HashiCorp Consul HTTP8501cmtp-mgt, cmtp-av8503lsp-self-ping8554RTSP alternate

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