Re: Sendmail question
From: Bill Vermillion (bv_at_wjv.com)
Date: 02/14/05
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Date: Sun, 13 Feb 2005 20:42:21 -0500 To: freebsd-isp@freebsd.org
I know you'll find this hard to believe, but on Sun, Feb 13, 2005 at 23:13 ,
Suporte Matik actually admitted to saying:
> On Sunday 13 February 2005 22:46, Noah Davidson wrote:
>
> > The only problem with that approach is that this is a back up
> > server and the users may not be able to know of all of the
> > users. Is there any way to not have all of these bounced mail
> > go to the postmaster / root account.
> sendmail should reject mail for nonexistent users by default
> and not forward to root unless you have any strange alias for
> all but you say bounced mail what confuses me a little bit, but
> anyway, isn't it that your systema accounts are exploited by
> the spammers ? so if having 10 domains you may get 10 spams for
> tty in your root mailbox, to prevent you may try this in your
> access:
> tty@ ERROR:"4.2.2:450 No such user here."
> and so on for each systema account and rebuild the access.db and
> probably your headache goes away
The problem I have is that when mail is bounced back mail from
spammers often comes from forged addresses and I get emails
from the far site indicating there are unknown users.
So I find routing noexistant users to /dev/null is more productive.
While it's not exactly the best way to do it, there are so many
bogus addresses sending mail I haven't found a good alternative.
One site we handle has one of those strong standalone names that
don't require any advertising to come up #1 on google or msn and
when it finally hit 300,000 spams/day for that one domain I took
out the MX records.
I use the access.db for blocking known places and I won't send
anything back at all - I used the DISCARD verb as sending messages
back does nothing but generate more traffic.
> >
> > ________________________________
> >
> > From: Bill Vermillion [mailto:bv@wjv.com]
> > Sent: Sun 2/13/2005 2:30 PM
> > To: Noah Davidson
> > Cc: FreeBSD-ISP List
> > Subject: Re: Sendmail question
> >
> >
> >
> > Ashes to ashes, and DOS to DOS Noah Davidson was heard to say
> >
> > on or about Sun, Feb 13, 2005 at 14:10 :
> > > I have set up a new FreeBSD box as mainly a backup mail server,
> > > although it is primary for a couple of domains. It is running
> > > sendmail 8.13.3 and it works fine, except for all the spam that
> > > is being sent to it to bad email addresses. I have aliased
> > > the root account to an email group on another server so that
> > > someone reads the root mail. The problem is that all the mail
> > > that spammers are sending to address that do not exist get
> > > bounced and the root account a notification (I believe it
> > > is the postmaster alias which is aliased to root). Is there
> > > any way to not have these notifications sent out. They are
> > > filling up the mail boxes. I just want the return to sender, but
> > > not to the root / postmaster as well. I have tried using the
> > > confCOPY_ERRORS_TO in my .mc file, but that just sends it to an
> > > additional account as well.
> >
> > Making assumptions that your sendmail is receiving bogus mail
> > for accounts that you have sendmail receive here is approach you
> > can take.
> >
> > Assume you have domains a.com b.com and c.com and your
> > local-host-names has those.
> >
> > Then you need to find out what users you have for each domain
> >
> > If you have curly larry and moe on a.com and no one else, then you
> > can build a virtualusrtable that looks like this.
> >
> > curly@a.com curly
> > larry@a.com larry
> > moe@a.com moe
> > @a.com nouser
> >
> > And the accnount 'nouser' will be in your /etc/mail/aliases
> > file and will look like this:
> >
> > nouser: /dev/null
> >
> > Run make in /etc/mail to create virtusertable.db and aliases.db
> > and that should get rid of the bogus names going to root.
> >
> > I find the virtualusertable to be quite handy for elminating a lot
> > of junk. It will only be a problem if you have a large user
> > base or lots of domains.
> >
> > Bill
> > --
> > Bill Vermillion - bv @ wjv . com
> >
> >
> > _______________________________________________
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> > http://lists.freebsd.org/mailman/listinfo/freebsd-isp
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>
> --
>
>
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-- Bill Vermillion - bv @ wjv . com _______________________________________________ freebsd-isp@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-isp To unsubscribe, send any mail to "freebsd-isp-unsubscribe@freebsd.org"
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