# systemd-socket-proxyd

## NAME



           systemd-socket-proxyd - Bidirectionally proxy local sockets to
           another (possibly remote) socket
    


## SYNOPSIS



    
           **systemd-socket-proxyd**[_OPTIONS_...] _HOST_ :_PORT_
    
           **systemd-socket-proxyd**[_OPTIONS_...] _UNIX-DOMAIN-SOCKET-PATH_
    


## DESCRIPTION



           **systemd-socket-proxyd** is a generic socket-activated network socket
           forwarder proxy daemon for IPv4, IPv6 and UNIX stream sockets. It
           may be used to bi-directionally forward traffic from a local
           listening socket to a local or remote destination socket.
    
           One use of this tool is to provide socket activation support for
           services that do not natively support socket activation. On behalf
           of the service to activate, the proxy inherits the socket from
           systemd, accepts each client connection, opens a connection to a
           configured server for each client, and then bidirectionally
           forwards data between the two.
    
           This utility's behavior is similar to socat(1). The main
           differences for **systemd-socket-proxyd** are support for socket
           activation with "Accept=no" and an event-driven design that scales
           better with the number of connections.
    
           Note that **systemd-socket-proxyd** will not forward socket side
           channel information, i.e. will not forward **SCM_RIGHTS** ,
           **SCM_CREDENTIALS** , **SCM_SECURITY** , **SO_PEERCRED** , **SO_PEERPIDFD** ,
           **SO_PEERSEC** , **SO_PEERGROUPS** and similar.
    


## OPTIONS



           The following options are understood:
    
           **-h** , **--help**
               Print a short help text and exit.
    
           **--version**
               Print a short version string and exit.
    
           **--connections-max=** , **-c**
               Sets the maximum number of simultaneous connections, defaults
               to 256. If the limit of concurrent connections is reached
               further connections will be refused.
    
               Added in version 233.
    
           **--exit-idle-time=**
               Sets the time before exiting when there are no connections,
               defaults to **infinity**. Takes a unit-less value in seconds, or a
               time span value such as "5min 20s".
    
               Added in version 246.
    


## EXIT STATUS



           On success, 0 is returned, a non-zero failure code otherwise.
    


## EXAMPLES



       **Simple Example**
           Use two services with a dependency and no namespace isolation.
    
           **Example 1. proxy-to-nginx.socket**
    
               [Socket]
               ListenStream=80
    
               [Install]
               WantedBy=sockets.target
    
           **Example 2. proxy-to-nginx.service**
    
               [Unit]
               Requires=nginx.service
               After=nginx.service
               Requires=proxy-to-nginx.socket
               After=proxy-to-nginx.socket
    
               [Service]
               Type=notify
               ExecStart=/usr/lib/systemd/systemd-socket-proxyd /run/nginx/socket
               PrivateTmp=yes
               PrivateNetwork=yes
    
           **Example 3. nginx.conf**
    
               [...]
               server {
                   listen       unix:/run/nginx/socket;
                   [...]
    
           **Example 4. Enabling the proxy**
    
               # systemctl enable --now proxy-to-nginx.socket
               $ curl http://localhost:80/
    
           If nginx.service has _StopWhenUnneeded=_ set, then passing
           **--exit-idle-time=** to **systemd-socket-proxyd** allows both services to
           stop during idle periods.
    
       **Namespace Example**
           Similar as above, but runs the socket proxy and the main service
           in the same private namespace, assuming that nginx.service has
           _PrivateTmp=_ and _PrivateNetwork=_ set, too.
    
           **Example 5. proxy-to-nginx.socket**
    
               [Socket]
               ListenStream=80
    
               [Install]
               WantedBy=sockets.target
    
           **Example 6. proxy-to-nginx.service**
    
               [Unit]
               Requires=nginx.service
               After=nginx.service
               Requires=proxy-to-nginx.socket
               After=proxy-to-nginx.socket
               JoinsNamespaceOf=nginx.service
    
               [Service]
               Type=notify
               ExecStart=/usr/lib/systemd/systemd-socket-proxyd 127.0.0.1:8080
               PrivateTmp=yes
               PrivateNetwork=yes
    
           **Example 7. nginx.conf**
    
               [...]
               server {
                   listen       8080;
                   [...]
    
           **Example 8. Enabling the proxy**
    
               # systemctl enable --now proxy-to-nginx.socket
               $ curl http://localhost:80/
    


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