HTTPfy

Port 365 (dtk)

IANA assigns port 365 to dtk: DTK.

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

IANA assignment

Service nameProtoDescriptionAssigneeReference
dtk TCP DTK Fred Cohen -
dtk UDP DTK Fred Cohen -

Check what is listening on port 365

Linux: is anything listening on TCP 365?
sudo ss -tlnp 'sport = :365'
Linux: UDP 365
sudo ss -ulnp 'sport = :365'
Linux / macOS: which process owns the port
sudo lsof -nP -i :365
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':365 '
Windows (Command Prompt)
netstat -ano | findstr :365
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 365 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 365
From Windows
Test-NetConnection HOST -Port 365
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 365

Block port 365 in the firewall

ufw
sudo ufw deny 365/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 365 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 365 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 365' -Direction Inbound -Protocol TCP -LocalPort 365 -Action Block
ufw
sudo ufw deny 365/udp
iptables
sudo iptables -A INPUT -p udp --dport 365 -j DROP
nftables
sudo nft add rule inet filter input udp dport 365 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 365' -Direction Inbound -Protocol UDP -LocalPort 365 -Action Block

Related ports

363rsvp-tunnel, rsvp_tunnel364aurora-cmgr366odmr367mortgageware

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