Port 8554 (TCP) — RTSP alt: what it is, how to check

Port 8554 RTSP alt · TCP

An alternative RTSP port, used by MediaMTX (rtsp-simple-server), some cameras and by RTSP servers that cannot bind 554 as non-root.

Port	8554
Transport	TCP
Service	RTSP alt — MediaMTX, cameras
Category	Media streaming
Range	registered (1024–49151)
Encrypted	No, plaintext
Exposure	Private network or VPN only

What runs on port 8554

An alternative RTSP port, used by MediaMTX (rtsp-simple-server), some cameras and by RTSP servers that cannot bind 554 as non-root. Same rules as 554.

Software that uses it: MediaMTX · IP cameras · live555 test servers

Should port 8554 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.

vlc rtsp://host:8554/stream to view; ffmpeg -rtsp_transport tcp when UDP packets get lost.

Check port 8554

# on the host: is anything listening, and which process?
ss -ltnp 'sport = :8554'
sudo lsof -i :8554

# from another machine: is it reachable?
nc -zv host 8554
nmap -p 8554 host
curl -v telnet://host:8554      # 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 8554

# ufw (Ubuntu/Debian)
sudo ufw allow from 10.0.0.0/8 to any port 8554 proto tcp
sudo ufw deny 8554/tcp

# nftables
nft add rule inet filter input ip saddr 10.0.0.0/8 tcp dport 8554 accept
nft add rule inet filter input tcp dport 8554 drop

# iptables (legacy)
iptables -A INPUT -p tcp --dport 8554 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 8554 -j DROP

# firewalld
sudo firewall-cmd --permanent --add-rich-rule='rule family=ipv4 source address=10.0.0.0/8 port port=8554 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 8554" 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 8554 TCP or UDP?

TCP. RTSP alt is a connection-oriented protocol; there is no UDP service on 8554 by default (a scanner reporting UDP 8554 open is usually seeing a filtered port).

Is port 8554 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 8554 is open?

On the server, ss -ltnp (or -lunp for UDP) shows whether something listens on 8554 and which process. From another machine, nc -zv host 8554 or nmap -p 8554 host tests reachability. "Open" in a scan means something answered; a firewall usually makes the port filtered (no answer) rather than closed (RST).

Can RTSP alt 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.