HTTPfy

Port 120 (cfdptkt)

IANA assigns port 120 to cfdptkt: CFDPTKT.

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

IANA assignment

Service nameProtoDescriptionAssigneeReference
cfdptkt TCP CFDPTKT John Ioannidis -
cfdptkt UDP CFDPTKT John Ioannidis -

Check what is listening on port 120

Linux: is anything listening on TCP 120?
sudo ss -tlnp 'sport = :120'
Linux: UDP 120
sudo ss -ulnp 'sport = :120'
Linux / macOS: which process owns the port
sudo lsof -nP -i :120
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':120 '
Windows (Command Prompt)
netstat -ano | findstr :120
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 120 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 120
From Windows
Test-NetConnection HOST -Port 120
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 120

Block port 120 in the firewall

ufw
sudo ufw deny 120/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 120 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 120 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 120' -Direction Inbound -Protocol TCP -LocalPort 120 -Action Block
ufw
sudo ufw deny 120/udp
iptables
sudo iptables -A INPUT -p udp --dport 120 -j DROP
nftables
sudo nft add rule inet filter input udp dport 120 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 120' -Direction Inbound -Protocol UDP -LocalPort 120 -Action Block

Related ports

118sqlserv119NNTP121erpc122smakynet

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