Internal Utilities

A few of the UML utilities are used by UML itself and are not meant to be used on their own.

• port-helper helps a UML instance use the host's telnetd server to accept telnet connections. This is used when attaching UML consoles and serial lines to host portals and xterms.

• uml_net is the setuid network setup helper. It is invoked by a UML instance whenever it needs to perform a network setup operation that it has no permissions for. This includes configuring network interfaces and establishing routes and proxy arp on the host. This is to ease the use of UML networking in casual use, where the root user inside the UML instance can be trusted. A secure UML configuration should not use uml_net and should instead use preconfigured TUN/TAP devices or uml_switch to communicate with the host.

• uml_watchdog is an external process used to track when a UML instance is running. It communicates with the UML harddog driver, expecting some communication at least once a minute. If that doesn't happen, uml_watchdog takes some action, either to kill the UML instance or to notify the administrator with an MConsole hang notification.