Port 6432 PgBouncer · TCP

What runs on port 6432

PgBouncer: the PostgreSQL connection pooler, by convention on 6432 so it can sit next to PostgreSQL on 5432. Applications point at 6432; PgBouncer keeps a small number of real server connections. Same access rules as PostgreSQL.

Software that uses it: PgBouncer · Supabase Supavisor, Neon pooler (same convention)

Should port 6432 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.

• Transaction pooling breaks prepared statements and session-level SET; choose the pool mode to match the application.

Check port 6432

# on the host: is anything listening, and which process?
ss -ltnp 'sport = :6432'
sudo lsof -i :6432

# from another machine: is it reachable?
nc -zv host 6432
nmap -p 6432 host
curl -v telnet://host:6432      # 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 6432

# ufw (Ubuntu/Debian)
sudo ufw allow from 10.0.0.0/8 to any port 6432 proto tcp
sudo ufw deny 6432/tcp

# nftables
nft add rule inet filter input ip saddr 10.0.0.0/8 tcp dport 6432 accept
nft add rule inet filter input tcp dport 6432 drop

# iptables (legacy)
iptables -A INPUT -p tcp --dport 6432 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 6432 -j DROP

# firewalld
sudo firewall-cmd --permanent --add-rich-rule='rule family=ipv4 source address=10.0.0.0/8 port port=6432 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 6432" with no source is just "open".

Related ports

• 5432 PostgreSQL

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