Reference Manual

NAME

setis - interact with the Interface Selection mechanism
setrr - interact with the Record Routes mechanism

setis [algorithm]
setrr [on | off]

When invoked with no argument, setis prints details of the current algorithm used for selecting a default route to the Internet.

Argument algorithm can have one of the following values:

    0    Use the interface with the best metric
    1    Use the interface with the best current total capacity
    2    Alternate between all available interfaces in a "round-robin" manner
    3    Select an interface at "random"
    4    Use only the Primary interface
    5    Use interfaces evenly

If algorithm 1, 2, 3 or 5 is selected, the command also turns on the Record Routes option. This setting can be modified with the command:

setrr [on | off]

The selected algorithm is not recorded in any configuration file or in the Windows Registry. To make the selection permanent, the needed command should be placed in file user.txt.

The NAT32 Primary Interface is the Internet-connected interface used to send and receive packets from the Internet. There must exist a default route for that interface.

The Primary interface can be set with the setp command, but it defaults to the interface for which the Main Internet Adapter checkbox was checked in the Interface Configuration dialog.

When several Internet-connected interfaces are available, only outgoing TCP connections can be routed via an alternative interface. All other traffic continues to be routed via the best interface (algorithm 0) or the Primary interface (algorithm 4).

When several Internet-connected interfaces are available, and algorithm 1, 2, 3 or 5 is selected, outgoing TCP connections cause a host-specific route to be added to the NAT32 Routing Table. This ensures that all traffic to the same IP address is routed via the same interface. The route is deleted 10 minutes after the last packet was forwarded via that route. The mechanism can be overridden with the command:

setrr [on | off]

Algorithm 5 attempts to spread traffic (input plus output) evenly over all Internet interfaces. Although this is not always possible (because of routing requirements), the traffic will even out over the longer term. To view the current interface usage, the command: routes count can be used.

The Source Route mechanism (if enabled) overrides the Interface Selection mechanism.

Route selection can also be modified by adding a Protocol and Destination Port specific route to the Routing Table. Such routes are often better matches than the default route for an interface and will therefore be chosen in preference to a default route. This mechanism cannot be used to bypass the Source Route mechanism.

netcfg, route, setht, setsr