Port 5222 (TCP) — XMPP client: what it is, how to check

Port 5222 XMPP client · TCP

XMPP client-to-server: Jabber chat, still the backbone of many push and presence systems (WhatsApp started on it, Apple Push is a cousin).

Port	5222
Transport	TCP
Service	XMPP client
Category	Chat and messaging
Range	registered (1024–49151)
Encrypted	Optional: plaintext with STARTTLS upgrade
Exposure	Designed to face the internet

What runs on port 5222

XMPP client-to-server: Jabber chat, still the backbone of many push and presence systems (WhatsApp started on it, Apple Push is a cousin). 5223 is the legacy implicit-TLS port, 5269 is server-to-server federation. Modern servers require STARTTLS on 5222.

Software that uses it: ejabberd · Prosody · Openfire · Conversations, Gajim, Dino (clients)

Should port 5222 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.

Federation needs 5269 open and SRV records (_xmpp-server._tcp) in DNS.

Check port 5222

# on the host: is anything listening, and which process?
ss -ltnp 'sport = :5222'
sudo lsof -i :5222

# from another machine: is it reachable?
nc -zv host 5222
nmap -p 5222 host
curl -v telnet://host:5222      # 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 5222

# ufw (Ubuntu/Debian)
sudo ufw allow from 10.0.0.0/8 to any port 5222 proto tcp
sudo ufw deny 5222/tcp

# nftables
nft add rule inet filter input ip saddr 10.0.0.0/8 tcp dport 5222 accept
nft add rule inet filter input tcp dport 5222 drop

# iptables (legacy)
iptables -A INPUT -p tcp --dport 5222 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 5222 -j DROP

# firewalld
sudo firewall-cmd --permanent --add-rich-rule='rule family=ipv4 source address=10.0.0.0/8 port port=5222 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 5222" 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 5222 TCP or UDP?

TCP. XMPP client is a connection-oriented protocol; there is no UDP service on 5222 by default (a scanner reporting UDP 5222 open is usually seeing a filtered port).

Is port 5222 encrypted?

Optional: plaintext with STARTTLS upgrade. The connection starts in plaintext and the client asks to upgrade; a server that accepts logins before the upgrade is the common weakness, so configure it to require TLS.

How do I check whether port 5222 is open?

On the server, ss -ltnp (or -lunp for UDP) shows whether something listens on 5222 and which process. From another machine, nc -zv host 5222 or nmap -p 5222 host tests reachability. "Open" in a scan means something answered; a firewall usually makes the port filtered (no answer) rather than closed (RST).

Can XMPP client 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.