Port 8118 (TCP) — Privoxy: what it is, how to check

Port 8118 Privoxy · TCP

Privoxy's default port: a filtering HTTP proxy often chained in front of Tor (9050) to give browsers an HTTP proxy interface.

Port	8118
Transport	TCP
Service	Privoxy — Filtering proxy, often in front of Tor
Category	Proxies
Range	registered (1024–49151)
Encrypted	No, plaintext
Exposure	Loopback or the host's own network only

What runs on port 8118

Privoxy's default port: a filtering HTTP proxy often chained in front of Tor (9050) to give browsers an HTTP proxy interface. Localhost only.

Software that uses it: Privoxy

Should port 8118 be open?

Loopback or the host's own network only. The service should listen on 127.0.0.1 (or a Unix socket) and be reached by a reverse proxy or by the application on the same host. If it answers on a public address, that is a misconfiguration.

forward-socks5t / 127.0.0.1:9050 . in the config is the Tor chaining line.

Check port 8118

# on the host: is anything listening, and which process?
ss -ltnp 'sport = :8118'
sudo lsof -i :8118

# from another machine: is it reachable?
nc -zv host 8118
nmap -p 8118 host
curl -v telnet://host:8118      # 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 8118

# ufw (Ubuntu/Debian)
sudo ufw allow from 10.0.0.0/8 to any port 8118 proto tcp
sudo ufw deny 8118/tcp

# nftables
nft add rule inet filter input ip saddr 10.0.0.0/8 tcp dport 8118 accept
nft add rule inet filter input tcp dport 8118 drop

# iptables (legacy)
iptables -A INPUT -p tcp --dport 8118 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 8118 -j DROP

# firewalld
sudo firewall-cmd --permanent --add-rich-rule='rule family=ipv4 source address=10.0.0.0/8 port port=8118 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 8118" with no source is just "open".

Related ports

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

Is port 8118 TCP or UDP?

TCP. Privoxy is a connection-oriented protocol; there is no UDP service on 8118 by default (a scanner reporting UDP 8118 open is usually seeing a filtered port).

Is port 8118 encrypted?

No, plaintext. Anything sent over it can be read by whoever is on the path, so it belongs on a trusted network or inside a VPN or SSH tunnel.

How do I check whether port 8118 is open?

On the server, ss -ltnp (or -lunp for UDP) shows whether something listens on 8118 and which process. From another machine, nc -zv host 8118 or nmap -p 8118 host tests reachability. "Open" in a scan means something answered; a firewall usually makes the port filtered (no answer) rather than closed (RST).

Can Privoxy run on a different port?

Yes; the number is a convention, not a requirement. Changing it reduces log noise from scanners but does not add security, and every client, firewall rule and monitoring check then needs the new number. Keep the default unless you have a concrete reason.