sendmail/mail/Mail

[Les Mikesell]

John Summerfield wrote:
> tony.chamberlain at lemko.com wrote:
>> note: for the following I am using made up names for anonymity of the 
>> actual names.
>>
>>
>> We have a customer, Acme, running Cent Os 4.5 with our software on it. 
>> When we encounter a problem we want to send mail to notify people. I 
>> am not asking how to do this because
>> we already know how. The problem is mail.
>>
>> The host name is myhost (I am making up names again remember). When I 
>> try to send mail from
>> it I eventually get returned mail, "the domain myhost.localdomain" 
>> does not exist (or something like
>> that). I realize I have to change the hostname to myhost.Acme.COM but 
>> I cant' change the hostname
>> via neat or in the files because it has other implications (mysql and 
>> some other software would be
>> affected).
>>
>> I tried, without a high expectation, doing something like this:
>>
>> HOSTNAME=myhost.Acme.COM
>> Mail tonychamberlain at lemko.com
>> <etc>
>>
>> but the mail still came back because that just changed the HOSTNAME 
>> variable in my env, not actually the
>> host name. Is there some way I can actually change hostname just for 
>> my environment to get mail sent,
>> without having to change it for the whole system?
>>
>>
>>
> the mail command just calls sendmail, it has no means of setting from.
> I think mutt can be coerced, but I've never tried.
> 
> If sendmail's idea of the host name is the same as you can see from the 
> Internet, then there shouldn't be a problem: Ffor examile
> 
> fff.example.com resolves to your client's IP address
> sendmail (or other MTA) thinks it's called fff.example.com
> then all will be well.
> 
> In practice, it doesn't matter what the name is so long as it resolves, 
> but it would be a bit rude to pinch IBM's.
> 
> In sendmail (and probably other MTA) you can also use address rewriting 
> (masquerading). See DM in sendmail.cf

You probably don't want to touch sendmail.cf (or even try to read 
it...).  Instead, be sure you have the sendmail-cf package installed, 
edit /etc/mail/sendmail.mc, and change
dnl MASQUERADE_AS(`mydomain.com')dnl
removing the leading dnl and replacing mydomain.com with something that 
is internet-legal.  If your software runs as root when it sends mail, 
you'll also need to add a leading dnl to the line:
EXPOSED_USER(`root')dnl
to comment it out.  Then restart sendmail.

-- 
   Les Mikesell
    lesmikesell at gmail.com