stupid sendmail

[John Summerfield]

Alexander Volovics wrote:
> As I have been using postfix a long time I have forgotten
> the little I knew about sendmail.
> But I thought it would have been configured by default to allow
> the mail from (ana)cron to work without problems and complaints.
> 
> On a laptop on which I have been trying out F8 test3 I decided to
> not use my standard postfix/mutt/fetchmail/procmail setup but make
> do with claws-mail instead. 
> So I just left sendmail (not needing it) with the default install
> configuration.
> 
> To my surprise I see constant error messages when getting mail from
> Mail Delivery Subsystem <MAILER-DAEMON at localhost.localdomain>
> Namely:
> - Tried to mail output of jon 'cron daily', but mailer proces
>   (usr/bin/sendmail) exited with status 65
> - The following addresses had permanent fatal errors -----
>   root
>     (reason: 553 5.5.4 <root at localhost.localdomain>... Real domain name
>      required for sender address) (expanded from: root)
> - relay localhost (127.0.0.1) may be forged
> 
> Eventually I do get the mail in /var/spool/mail/user and claws-mail
> picks it up (again with a summary of the errors).
> 
> Wouldn't it be neater to configure sendmail to perform these simple
> duties without these hiccups.
> I expect that if /etc/aliases is not changed to deliver root's mail to
> user the user might never get any cron mail and newbies might be
> confused on seeing possible error messages when mail is delivered
> to root.
> 
> A further irritation occurs when using 'mail' to send messages from
> user to user. The do not arrive at /var/spool/mail/user but are dropped
> as "dead.letter" in the users home directory
> 
> Is this mentioned somewhere. It should be.

Sendmail deduces the from: user's email address from the domain name of 
the system. I am sure that it can be set properly in 
/etc/mail/sendmail.*, but being a postfix user I don't care to check. 
However, postfix also needs to be configured: on my desktop whose 
hostname is numbat.demo.lan, mail sent with the mail command isn't 
accessible outside my LAN because sensible folk reject/discard email 
from domains they can't resolve.

Note that the mail command does little more than pretty-up the email and 
feed it into sendmail's stdin. The beautification doesn't extend to 
setting the from: address. cron simply used the mail command to send email.



-- 

Cheers
John

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