HTTPfy

Port 3942 (srdp)

IANA assigns port 3942 to srdp: satellite distribution.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
srdp TCP satellite distribution Simone Molendini -
srdp UDP satellite distribution Simone Molendini -

Registry dates for this port: registered 2003-11.

Check what is listening on port 3942

Linux: is anything listening on TCP 3942?
sudo ss -tlnp 'sport = :3942'
Linux: UDP 3942
sudo ss -ulnp 'sport = :3942'
Linux / macOS: which process owns the port
sudo lsof -nP -i :3942
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':3942 '
Windows (Command Prompt)
netstat -ano | findstr :3942
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 3942 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 3942
From Windows
Test-NetConnection HOST -Port 3942
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 3942

Block port 3942 in the firewall

ufw
sudo ufw deny 3942/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 3942 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 3942 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 3942' -Direction Inbound -Protocol TCP -LocalPort 3942 -Action Block
ufw
sudo ufw deny 3942/udp
iptables
sudo iptables -A INPUT -p udp --dport 3942 -j DROP
nftables
sudo nft add rule inet filter input udp dport 3942 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 3942' -Direction Inbound -Protocol UDP -LocalPort 3942 -Action Block

Related ports

3940xecp-node3941homeportal-web3943tig3944sops

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