How to Configure NIS+ and DNS for sendmail

This list includes all the configuration issues that you must resolve before using sendmail when using NIS+ with DNS as your name service.

mail domain name

If you are setting up NIS+ as your primary name service, sendmail can look up the mail domain from the NIS+ sendmailvars table, a two-column NIS+ table with one key column and one value column. To set up your mail domain, you must add one entry to this table. This entry should have the key column set to the literal string maildomain and the value column set to the your mail domain name (for example, admin.acme.com). Although NIS+ allows any string in the sendmailvars table, the suffix rule still applies for the mail system to work correctly. You can use nistbladm to add the maildomail entry to the sendmailvars table. For example:

nistbladm -A key="maildomain" value=<mail domain> sendmailvars.org_dir.<NIS+ domain>

Note that this mail domain is a suffix of the NIS+ domain.

mailhost host name

If your network uses both NIS+ and DNS as the source for the host database, you can put the mailhost entry in either the NIS+ or DNS host table. Make sure that your users list NIS+ and DNS as the source for the host database in the /etc/nsswitch.conf file.

full host names

Both NIS+ and DNS "understand" full host names. Following the regular NIS+ and DNS setup procedures satisfies this requirement.

matching full and short host names

For every host entry in the NIS+ host table, you must have a corresponding host entry in DNS.

multiple NIS domains in one mail domain

To satisfy this requirement, you can duplicate the entries in all the host tables, or you can type all host entries in the user name service domains into a master host table at mail domain level.