Date: Sun, 20 Jul 1997 19:22:05 -0600 (MDT) From: John-David Childs <jdc@denver.net> To: dkelly@HiWAAY.net Cc: questions@FreeBSD.ORG Subject: Re: Sendmail and mail hub Message-ID: <Pine.BSI.3.95.970720185116.6492A-100000@milehigh.denver.net> In-Reply-To: <199707202357.SAA24276@nexgen.hiwaay.net>
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On Sun, 20 Jul 1997 dkelly@HiWAAY.net wrote: > Finally many sites are clamping down their sendmails to ward off spam. This > bites me as my machine thinks its 10.1.0.1 and ID's as such. And with an You should have given your machine a hostname. Sendmail will use the hostname when connecting to another mailer, and your mail user agent (pine, elm, /usr/bin/mail, etc.) will use it too. > unresolvable address like that many sites refuse mail from me. However at Yep. My sendmail refuses messages from unresolvable hosts. On certain messages from certain hosts, I use the domaintable feature to rewrite incoming headers from an unresolvable hostname to a resolvable name in the same domain (i.e. if hostX doesn't have a DNS record for security reasons, but sometimes sends mail to a customer, I use the domaintable to rewrite hostx.subdomain.domain -> subdomain.domain In your case, your mail user agent should have a method for defining your email address as dkelley@hiwaay.net. Thus, even though you are sending from your own machine (which theoretically could be anything...don't use a real domain name without permission of course) you can pick up your mail off hiwaay.net's mailserver. Other strategies include: registering a domain and asking your ISP to host it asking your ISP if they'll define a hostname for you and give it an MX record pointing to their mailserver > this moment I'm also tnt1-47.HiWAAY.net. If sendmail knew to use that net > name then I think my problem will be solved. > If that is a dynamically assigned IP address/name, it won't help you at all. If I try to send mail to that address right now, it'll end up being refused (in 99% of cases people don't run their own SMTP daemons) or in someone else's mail file ;( > The other option is to forward all outgoing mail to my ISP at > mail.hiwaay.net and let them handle delivery. Studying the bat book, > http://www.sendmail.org, the docs in /usr/src/usr.sbin/sendmail, FreeBSD > FAQ and handbook, etc., my head is spinning. Yes, but it's far easier to send mail directly via Sendmail as you've been doing, but defining your email address to be whatever it would be if you were using hiwaay.net's SMTP server (e.g. dkelley@hiwaay.net) > > So I've started hacking on /etc/sendmail.cf just to see what kind of > trouble I can get into (I'm the only user of this system, so I can only > hurt myself, right?). This looked interesting in /etc/sendmail.cf: > > # "Smart" relay host (may be null) > DS > > So I changed it to: > > # "Smart" relay host (may be null) > #DS > DSmail.hiwaay.net That works too. > > Elsewhere I did the same thing for: > > # who I masquerade as (null for no masquerading) (see also $=M) > DMmail.hiwaay.net > BAD! Your ISP will shoot you. You should not masquerade as another host without permission. > So that's the background. The Real Question(s) are: > > 1) Is "Smart" relay host the Right Way to handle my problem? Have I done > something that will bite me later? > That's certainly one way to do it. > 2) How should I name my FreeBSD box which is not a full time system in the > hiwaay.net domain? Ask your ISP. It takes just a few seconds to add a hostname/MX record for you. If you wanted to be dkelley.hiwaay.net, they would just add dkelley IN MX 5 mail.hiwaay.net. to their DNS file for hiwaay.net and add dkelly.hiwaay.net to the /etc/sendmail.cw file. They might charge you for this service. You might also find out if they'll sell you a static IP. Then they could do this: dkelley IN A X.X.X.X IN MX 5 dkelley.hiwaay.net. IN MX 10 mail.hiwaay.net. (Mail would queue on mail.hiwaay.net if you weren't online). -- John-David Childs (JC612) @denver.net/Internet-Coach System Administrator Enterprise Internet Solutions & Network Engineer 901 E 17th Ave, Denver 80218 Did you know that if you took all the economists in the world and lined them up end to end, they'd still point in the wrong direction?
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