Notes

[1]This is usually /usr/sbin on 4.4BSD and newer systems; many systems install it in /usr/lib. I understand it is in /usr/ucblib on System V Release 4.

[2]Some vendors ship them owned by bin; this creates a security hole that is not actually related to sendmail. Other important directories that should have restrictive ownerships and permissions are /bin, /usr/bin, /etc, /usr/etc, /lib, and /usr/lib.

[3]Actually, the pathname varies depending on the operating system; /etc is the preferred directory. Some older systems install it in /usr/lib/sendmail.cf, and I've also seen it in /usr/ucblib and /etc/mail. If you want to move this file, change src/conf.h.

[4]The system libraries can reference other files; in particular, system library subroutines that sendmail calls probably reference /etc/passwd and /etc/resolv.conf.

[5]Except on Ultrix, which does not support facilities in the syslog.

[6]This format may vary slightly if your vendor has changed the syntax.

[7]Actually, any mailer that has the `A' mailer flag set will permit aliasing; this is normally limited to the local mailer.

[8]The gdbm package probably works as well.

[9]The AliasWait option is required in the configuration for this action to occur. This should normally be specified.

[10]That is, it sets its effective uid to the real uid; thus, if you are executing as root, as from root's crontab file or during system startup the root permissions will still be honored.

[11]On some systems the default is zero to turn the protocol off entirely.

[12]This verification includes looking up every address with the name server; this involves network delays, and can in some cases can be considerable.

[13]This is actually completely equivalent to $(host hostname$). In particular, a $: default can be used.

[14]You may want to use it for special per user extensions. For example, in the address jgm+foo@CMU.EDU; the +foo part is not part of the user name, and is passed to the local mailer for local use.

[15]As of version 8.6, all of these macros have reasonable defaults. Previous versions required that they be defined.

[16]For example, on some systems gethostname might return foo which would be mapped to foo.bar.com by gethostbyname.

[17]Older versions of sendmail didn't pre-define $j at all, so up until 8.6, config files always had to define $j.

[18]The old g option has been combined into the DefaultUser option.

[19]And of course, vendors are encouraged to add themselves to the list of recognized vendors by editing the routine setvendor in conf.c. Please send e-mail to sendmail@CS.Berkeley.EDU to register your vendor dialect.

[20]That is, don't create new maps and then use mv(1) to move them into place. Since the maps are already open the new maps will never be seen.

[21]These instructions are known to be incomplete. A future version of the user database is planned including things such as finger service -- and good documentation.

[22]Actually, this is no longer true in SMTP; this information is contained in the envelope. The older ARPANET protocols did not completely distinguish envelope from header.

[23]If you do, please send updates to sendmail@CS.Berkeley.EDU.

*Deprecated.

[25]This example is contrived and probably inaccurate for your environment. Glance over it to get an idea; nothing can replace looking at what your own system generates.