#### 3.12.1 Using `mda` with Sendmail. ¶

When used with Sendmail, `mda` must be invoked from the local mailer definition in the `sendmail.cf` file. The flags ‘`lswS`’ must be set for the mailer. These mean: the mailer is local, quote characters should be stripped off the address before invoking the mailer, the user must have a valid account on this machine and the userid should not be reset before calling the mailer. Additionally, the ‘`fn`’ flags may be specified to allow `mda` to generate the usual ‘`From` ’ envelope instead of the one supplied by `sendmail`.

If you wish to use `mda` with non-local authentication, such as SQL or LDAP, you also need to remove the ‘`w`’ flag, since in that case the user is not required to have a valid account on the machine that runs `sendmail`.

Here is an example of mailer definition in `sendmail.cf`

    Mlocal, P=/usr/local/sbin/mda,
            F=lsDFMAw5:/|@qSPfhn9,
            S=EnvFromL/HdrFromL, R=EnvToL/HdrToL,
            T=DNS/RFC822/X-Unix,
            A=mail $u

To define local mailer in ‘`mc`’ source file, it will suffice to set:

    define(`LOCAL_MAILER_PATH', `/usr/local/sbin/mda')
    define(`LOCAL_MAILER_ARGS', `mail $u')