Port 1935 (RTMP)

Real-Time Messaging Protocol, still the standard way to push live streams from OBS to YouTube, Twitch and media servers (nginx-rtmp, SRS).

Registered (user) port, 1024-49151 TCP Streaming Expose only to trusted sources

What port 1935 is used for

Real-Time Messaging Protocol, still the standard way to push live streams from OBS to YouTube, Twitch and media servers (nginx-rtmp, SRS).

Expose only to trusted sources. Protect ingest with stream keys and do not expose an open RTMP server, or anyone can publish streams to it.

Service nameProtoDescriptionAssigneeReference

macromedia-fcs TCP Macromedia Flash Communications Server MX Pritham Shetty -

macromedia-fcs UDP Macromedia Flash Communications server MX Pritham Shetty -

Linux: is anything listening on TCP 1935?

sudo ss -tlnp 'sport = :1935'

Linux / macOS: which process owns the port

sudo lsof -nP -i :1935

Older Linux / BSD (net-tools)

sudo netstat -tlnp | grep ':1935 '

Windows (Command Prompt)

netstat -ano | findstr :1935

Windows (PowerShell)

Get-NetTCPConnection -LocalPort 1935 -State Listen | Select LocalAddress,OwningProcess

From another machine

nc -vz -w 5 HOST 1935

From Windows

Test-NetConnection HOST -Port 1935

Replace 203.0.113.10 with the address or network you trust. With ufw, make sure the default incoming policy is deny.

ufw (one trusted source)

sudo ufw allow from 203.0.113.10 to any port 1935 proto tcp

iptables

sudo iptables -A INPUT -p tcp --dport 1935 -s 203.0.113.10 -j ACCEPT
sudo iptables -A INPUT -p tcp --dport 1935 -j DROP

nftables

sudo nft add rule inet filter input ip saddr 203.0.113.10 tcp dport 1935 accept
sudo nft add rule inet filter input tcp dport 1935 drop

Windows Firewall

New-NetFirewallRule -DisplayName 'TCP 1935 trusted' -Direction Inbound -Protocol TCP -LocalPort 1935 -RemoteAddress 203.0.113.10 -Action Allow

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Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.