Port 6697 (IRC over TLS)

IRC with TLS (ircs-u), the standard secure port on Libera.Chat, OFTC and others.

Registered (user) port, 1024-49151 TCP Voice, video and chat Meant to face the internet

What port 6697 is used for

IRC with TLS (ircs-u), the standard secure port on Libera.Chat, OFTC and others.

Meant to face the internet. Fine to expose for IRC servers.

Service nameProtoDescriptionAssigneeReference

ircs-u TCP Internet Relay Chat via TLS/SSL - RFC 7194

Registry dates for this port: registered 2014-02-11.

Linux: is anything listening on TCP 6697?

sudo ss -tlnp 'sport = :6697'

Linux / macOS: which process owns the port

sudo lsof -nP -i :6697

Older Linux / BSD (net-tools)

sudo netstat -tlnp | grep ':6697 '

Windows (Command Prompt)

netstat -ano | findstr :6697

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 6697 -State Listen | Select LocalAddress,OwningProcess

From another machine

nc -vz -w 5 HOST 6697

From Windows

Test-NetConnection HOST -Port 6697

ufw

sudo ufw allow 6697/tcp

iptables

sudo iptables -A INPUT -p tcp --dport 6697 -j ACCEPT

nftables

sudo nft add rule inet filter input tcp dport 6697 accept

Windows Firewall

New-NetFirewallRule -DisplayName 'Allow TCP 6697' -Direction Inbound -Protocol TCP -LocalPort 6697 -Action Allow

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Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.