Network

Network

See also: protocol, authentication, encryption and multicast DNS

Connection Types

Type	Bind option	Availability	Information
TCP	bind-tcp	All
QUIC	bind-quic	All
SSL	bind-ssl	All
SSH	bind-ssh	All
WebSocket	bind-ws	All
Secure WebSocket	bind-wss	All
RFB	bind-rfb	desktop and shadow servers only	Allows VNC clients to connect
unix domain socket	bind	Posix	Local connections or via SSH
named-pipe	bind	MS Windows	#1150
vsock	bind-vsock	Linux	host - guest virtual machines connections - see #983

TCP sockets can also be upgraded transparently to (Secure) WebSocket, SSL, SSH and RFB, so a single TCP port can support 6 different protocols automatically.
Unencrypted modes like plain-TCP and plain-WebSocket can also be secured with AES.
All the sockets that can be accessed via a network connection (all but vsock and named-pipe) will usually be published via multicast DNS. On Posix, unix-domain-sockets are exposed as SSH as we assume that a local SSH server is always available.

By default, local unix domain sockets (--bind=auto which is the default) also create abstract sockets, use --bind=noabstract if needed.

See also: Security Considerations

Examples:

TCP Upgrade to WebSocket

xpra start --start=xterm --bind-tcp=0.0.0.0:10000

xpra attach ws://localhost:10000/

The same address (10000 here) can also be opened in a browser to use the HTML5 client:

xdg-open http://localhost:10000/

SSH with password file

echo -n thepassword > password.txt
xpra start --start=xterm --bind-ssh=0.0.0.0:10000,auth=file,filename=password.txt

xpra attach ssh://localhost:10000/

The client will prompt for the password, as found in the password.txt file and not the regular shell account password.

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Network Performance

Xpra will try to detect your network adapter and connection characteristics, and it should adapt to changing network capacity and performance. However, it may not always get it right, and you may need to turn off bandwidth detection (bandwidth-detection option) and / or specify your own bandwidth constraints. (bandwidth-limit option).

You can see how much bandwidth is used and how good the picture latency is using the "Graphs" tab of the "Session Info" dialog found in Xpra's system tray menu:

More network information is available elsewhere in the "Session Info" dialog or via the "xpra info" command:

network latency via xpra info

$ xpra info | egrep -i "network|latency"
(..)
client.latency.50p=3
client.latency.80p=3
client.latency.90p=3
client.latency.absmin=1
(..)

The performance of xpra will be affected by your network connection speed, in particular bufferbloat is known to cause severe performance degradations as xpra is quite sensitive to network jitter and latency, try to eliminate bufferbloat in your network.

QUIC should offer the lowest latency, though it may need some tuning.

See A little bump in the wire that makes your Internet faster, bufferbloat faq.

For Linux systems, Queueing in the Linux Network Stack is recommended reading.