HTTPfy

Port 3961 (proaxess)

IANA assigns port 3961 to proaxess: ProAxess Server.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
proaxess TCP ProAxess Server Jonas Ahlqvist -
proaxess UDP ProAxess Server Jonas Ahlqvist -

Registry dates for this port: registered 2005-08.

Check what is listening on port 3961

Linux: is anything listening on TCP 3961?
sudo ss -tlnp 'sport = :3961'
Linux: UDP 3961
sudo ss -ulnp 'sport = :3961'
Linux / macOS: which process owns the port
sudo lsof -nP -i :3961
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':3961 '
Windows (Command Prompt)
netstat -ano | findstr :3961
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 3961 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 3961
From Windows
Test-NetConnection HOST -Port 3961
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 3961

Block port 3961 in the firewall

ufw
sudo ufw deny 3961/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 3961 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 3961 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 3961' -Direction Inbound -Protocol TCP -LocalPort 3961 -Action Block
ufw
sudo ufw deny 3961/udp
iptables
sudo iptables -A INPUT -p udp --dport 3961 -j DROP
nftables
sudo nft add rule inet filter input udp dport 3961 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 3961' -Direction Inbound -Protocol UDP -LocalPort 3961 -Action Block

Related ports

3959treehopper3960bess3962sbi-agent3963thrp

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