Mx, nomx, nodns, defaultmx, randommx, nonrandommx, nameservers, defaultnameservers Channel Options

From MsgServerDocWiki

Jump to: navigation, search


TCP/IP nameserver and MX record support (mx, nomx, nodns, defaultmx, randommx, nonrandommx, nameservers, defaultnameservers)

Most TCP/IP networks support the use of MX (mail forwarding) records but a few do not. The MTA's TCP/IP channel programs can be configured to not use MX records if they are not provided by the network to which the MTA system is connected. Some TCP/IP channel programs can be configured to not do DNS (nameserver) lookups at all. randommx specifies that MX lookups should be done and MX record values of equal precedence should be processed in random order. nonrandommx specifies that MX lookups should be done and MX values of equal precedence should be processed in the same order in which they were received. The mx option is currently equivalent to nonrandommx; it may change to be equivalent to randommx in a future release. The nomx option disables MX lookups. The defaultmx option specifies that mx should be used if the network says that that MX records are supported.

The default is defaultmx on channels that support MX lookups in any form.

On UNIX, whether the underlying TCP/IP package's local host tables are used in addition to the DNS for lookups is up to the underlying TCP/IP package configuration. Generally, TCP/IP packages are configured so that local host tables will indeed be consulted. Consult your TCP/IP package documentation for details.

When nameserver lookups are being performed, that is, unless the nodns channel option is used on OpenVMS, or the nsswitch.conf file on UNIX or the NT TCP/IP configuration selects no use of nameservers, then the nameserver channel option may be used to specify a list of nameservers to consult rather than consulting the TCP/IP stack's own choice of nameservers. nameservers requires a space separated list of IP addresses for the nameservers, e.g., 

1.2.3.1 1.2.3.2

defaultnameserversis the default, and means to use the TCP/IP stack's own choice of nameservers.

Retrieved from "http://msg.wikidoc.info/index.php/Mx%2C_nomx%2C_nodns%2C_defaultmx%2C_randommx%2C_nonrandommx%2C_nameservers%2C_defaultnameservers_Channel_Options"
Personal tools