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Port 3667 (infoexch)

IANA assigns port 3667 to infoexch: IBM Information Exchange.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
infoexch TCP IBM Information Exchange Paul Ford Hutchinson -
infoexch UDP IBM Information Exchange Paul Ford Hutchinson -

Registry dates for this port: registered 2003-01.

Check what is listening on port 3667

Linux: is anything listening on TCP 3667?
sudo ss -tlnp 'sport = :3667'
Linux: UDP 3667
sudo ss -ulnp 'sport = :3667'
Linux / macOS: which process owns the port
sudo lsof -nP -i :3667
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':3667 '
Windows (Command Prompt)
netstat -ano | findstr :3667
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 3667 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 3667
From Windows
Test-NetConnection HOST -Port 3667
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 3667

Block port 3667 in the firewall

ufw
sudo ufw deny 3667/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 3667 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 3667 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 3667' -Direction Inbound -Protocol TCP -LocalPort 3667 -Action Block
ufw
sudo ufw deny 3667/udp
iptables
sudo iptables -A INPUT -p udp --dport 3667 -j DROP
nftables
sudo nft add rule inet filter input udp dport 3667 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 3667' -Direction Inbound -Protocol UDP -LocalPort 3667 -Action Block

Related ports

3665ent-engine3666eserver-pap3668dell-rm-port3669casanswmgmt

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