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Port 668 (mecomm)

IANA assigns port 668 to mecomm: MeComm.

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

IANA assignment

Service nameProtoDescriptionAssigneeReference
mecomm TCP MeComm - -
mecomm UDP MeComm - -

Check what is listening on port 668

Linux: is anything listening on TCP 668?
sudo ss -tlnp 'sport = :668'
Linux: UDP 668
sudo ss -ulnp 'sport = :668'
Linux / macOS: which process owns the port
sudo lsof -nP -i :668
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':668 '
Windows (Command Prompt)
netstat -ano | findstr :668
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 668 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 668
From Windows
Test-NetConnection HOST -Port 668
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 668

Block port 668 in the firewall

ufw
sudo ufw deny 668/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 668 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 668 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 668' -Direction Inbound -Protocol TCP -LocalPort 668 -Action Block
ufw
sudo ufw deny 668/udp
iptables
sudo iptables -A INPUT -p udp --dport 668 -j DROP
nftables
sudo nft add rule inet filter input udp dport 668 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 668' -Direction Inbound -Protocol UDP -LocalPort 668 -Action Block

Related ports

666doom667disclose669meregister670vacdsm-sws

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