Port 26379 Redis Sentinel · TCP

What runs on port 26379

Redis Sentinel: monitors Redis masters and replicas and performs automatic failover. Clients ask Sentinel for the current master. Same network rules as Redis itself.

Software that uses it: Redis Sentinel · Valkey Sentinel

Should port 26379 be open?

Private network or VPN only. Nothing good comes from this port being reachable from the internet. Keep it on an internal network, reach it over a VPN or an SSH tunnel, and firewall it from everything that does not need it.

• redis-cli -p 26379 sentinel masters shows what it is monitoring and the current master address.

Check port 26379

# on the host: is anything listening, and which process?
ss -ltnp 'sport = :26379'
sudo lsof -i :26379

# from another machine: is it reachable?
nc -zv host 26379
nmap -p 26379 host
curl -v telnet://host:26379      # 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 26379

# ufw (Ubuntu/Debian)
sudo ufw allow from 10.0.0.0/8 to any port 26379 proto tcp
sudo ufw deny 26379/tcp

# nftables
nft add rule inet filter input ip saddr 10.0.0.0/8 tcp dport 26379 accept
nft add rule inet filter input tcp dport 26379 drop

# iptables (legacy)
iptables -A INPUT -p tcp --dport 26379 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 26379 -j DROP

# firewalld
sudo firewall-cmd --permanent --add-rich-rule='rule family=ipv4 source address=10.0.0.0/8 port port=26379 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 26379" with no source is just "open".

Related ports

• 6379 Redis — No auth by default; never expose
• 16379 Redis Cluster bus — Data port + 10000

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