Port 119 NNTP · TCP

What runs on port 119

NNTP: Usenet news. Still alive for the binary newsgroups and a few text hierarchies; most providers now use NNTPS on 563. Also used internally by some mailing-list gateways.

Software that uses it: INN · Leafnode · Thunderbird (client) · SABnzbd/NZBGet (clients)

Should port 119 be open?

Designed to face the internet. This port exists to be reachable from anywhere, so the usual question is not whether to open it but how the service behind it is configured and patched.

• Commercial providers almost all require TLS on 563 and authentication.

Check port 119

# on the host: is anything listening, and which process?
ss -ltnp 'sport = :119'
sudo lsof -i :119

# from another machine: is it reachable?
nc -zv host 119
nmap -p 119 host
curl -v telnet://host:119      # raw TCP connect test, Ctrl-C to leave

A port that answers from the internet when it should not is the finding; nmap from a machine outside your network (or a VPS) is the honest test, because scans from inside the LAN pass the firewall you are trying to verify.

Allow or block port 119

# ufw (Ubuntu/Debian)
sudo ufw allow from 10.0.0.0/8 to any port 119 proto tcp
sudo ufw deny 119/tcp

# nftables
nft add rule inet filter input ip saddr 10.0.0.0/8 tcp dport 119 accept
nft add rule inet filter input tcp dport 119 drop

# iptables (legacy)
iptables -A INPUT -p tcp --dport 119 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 119 -j DROP

# firewalld
sudo firewall-cmd --permanent --add-rich-rule='rule family=ipv4 source address=10.0.0.0/8 port port=119 protocol=tcp accept'

Replace 10.0.0.0/8 with the networks that need access. Allowing by source address is the rule that matters; "allow 119" with no source is just "open".

Related ports

• 563 NNTPS — Usenet over TLS
• 25 SMTP — Mail transfer between servers

Part of the port number reference. Ports are 16-bit numbers; see also the subnet calculator and the packet decoder, which shows ports inside TCP and UDP headers.

Questions