The checkaddr program is used to check the validity of an address with the local mail system (MMDF). Checkaddr can be given addresses either on the command line, one address per argument, or a list of addresses can be given to checkaddr on the standard input, one address per line. The latter mode is use for checking the addresses in a mailing list by saying ``checkaddr < mailing-list-file''. Checkaddr will announce each address on a separate line and follow the address with its status (normally ``OK''). Checkaddr uses the MMDF program submit to do the address verification.
If the -w option is given, checkaddr cause submit to generate detailed submission tracing. This can sometimes be useful to help find problems in alias files or mailing lists.