# 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.

## 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.