Port 6514 syslog over TLS · TCP

What runs on port 6514

Syslog over TLS (RFC 5425): encrypted, authenticated, reliable log shipping. The right choice for sending logs across the internet or between sites; rsyslog and syslog-ng both support it with certificates.

Software that uses it: rsyslog (omfwd with gtls) · syslog-ng · Graylog, Splunk inputs

Should port 6514 be open?

Internet-facing only with authentication and care. It can be exposed when the service behind it is authenticated, rate-limited and kept up to date; most deployments are better off behind a VPN, an allow-list or a reverse proxy.

• Mutual TLS (client certificates) stops anyone from injecting fake log lines into your SIEM.

Check port 6514

# on the host: is anything listening, and which process?
ss -ltnp 'sport = :6514'
sudo lsof -i :6514

# from another machine: is it reachable?
nc -zv host 6514
nmap -p 6514 host
curl -v telnet://host:6514      # 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 6514

# ufw (Ubuntu/Debian)
sudo ufw allow from 10.0.0.0/8 to any port 6514 proto tcp
sudo ufw deny 6514/tcp

# nftables
nft add rule inet filter input ip saddr 10.0.0.0/8 tcp dport 6514 accept
nft add rule inet filter input tcp dport 6514 drop

# iptables (legacy)
iptables -A INPUT -p tcp --dport 6514 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 6514 -j DROP

# firewalld
sudo firewall-cmd --permanent --add-rich-rule='rule family=ipv4 source address=10.0.0.0/8 port port=6514 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 6514" with no source is just "open".

Related ports

• 514 syslog — Remote logging (tcp 514 is rsh/rlogin historically)
• 601 syslog (TCP) — IANA-registered reliable syslog

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