Hi there,

I have a mail gateway installed with version 8.13.7 of sendmail with
all the patches. it is only a mail gateway and forwards all the mails
to another mail server or send the mails out to the internet. So
problem i face at the moment is for example my domain is xyz.com . when
somebody sends a mail to us and puts as from the domain xyz.com, the
mail server accept the mail. I think in normal behaviour the mail
should be rejected since the mail is not coming from one of our
networks.

where do i have to configure sendmail to reject emails coming from the
internet and having in the from field our domain name?

here is the mc file i used for the sendmail.cf:

divert(0)dnl
VERSIONID(`$Id: generic-solaris.mc,v 8.13 2001/06/27 21:46:30 gshapiro
Exp $')
OSTYPE(solaris2)dnl
DOMAIN(generic)dnl
FEATURE(access_db)dnl
FEATURE(mailertable)dnl
MAILER(local)dnl
MAILER(smtp)dnl
define(`confPRIVACY_FLAGS', `authwarnings,goaway,noetrn')dnl
define(`confTO_IDENT', `0')dnl


thanks a lot for your .

ycae

ycae77@gmail.com wrote:

> where do i have to configure sendmail to reject emails coming from the
> internet and having in the from field our domain name?

Sendmail doesn't read the "from field" (or "From: " header) of an
incoming message. It only knows about the envelope sender. What you
want to do is possible using a milter.

--
----------------------------------------------------------------------
Sylvain Robitaille syl@alcor.concordia.ca

Systems and Network analyst Concordia University
Instructional & Information Technology Montreal, Quebec, Canada
----------------------------------------------------------------------

Sylvain Robitaille <syl@alcor.concordia.ca> writes:

> ycae77@gmail.com wrote:
>
> > where do i have to configure sendmail to reject emails coming from the
> > internet and having in the from field our domain name?
>
> Sendmail doesn't read the "from field" (or "From: " header) of an
> incoming message. It only knows about the envelope sender. What you
> want to do is possible using a milter.

Well, it is possible to write header check rulesets, which can reject
mail.

These header check rulesets however do not get address from header as input
but instead they got whole header as input.

On sendmail distribution there is example for testing Message-Id
header, but same kind checking can be used also for other headers.

>
> --
> ----------------------------------------------------------------------
> Sylvain Robitaille syl@alcor.concordia.ca
>
> Systems and Network analyst Concordia University
> Instructional & Information Technology Montreal, Quebec, Canada
> ----------------------------------------------------------------------

/ Kari Hurtta

Kari Hurtta wrote:

> it is possible to write header check rulesets, which can reject mail.

Alright, I stand corrected, but counter that what the OP wants, then, is
_easier_ to do with a milter ... :-)

--
----------------------------------------------------------------------
Sylvain Robitaille syl@alcor.concordia.ca

Systems and Network analyst Concordia University
Instructional & Information Technology Montreal, Quebec, Canada
----------------------------------------------------------------------

ok i understand your points but shouldn't it be that sendmail accepts
all incoming email from the internet but not the ones where the from
address is the same as the ones sendmail is responsible for?

i tried to use the local-domains file but than sendmail tries to do a
verify of the user to see if the user exists but since the users are
not defined on this server, all the mails are rejected. what about if i
would remove the MAILER(local) from the mc file and only keep the
MAILER(smtp)?

thanks for your ,
Ycae

Sylvain Robitaille <syl@alcor.concordia.ca> writes:

> Kari Hurtta wrote:
>
> > it is possible to write header check rulesets, which can reject mail.
>
> Alright, I stand corrected, but counter that what the OP wants, then, is
> _easier_ to do with a milter ... :-)

What questioner wants is bad idea.

Anyway perhaps like that:

LOCAL_RULESETS
HFrom: $>CheckFrom

SCheckFrom
R $*@$=w $#error $: "553 I do not like your From header"
R $*<$*@$=w> $#error $: "553 I do not like your From header"

This do not catch all cases and is bad idea :-)
Note that this ruleset ignores comments on From: -header.


(Hmm. Actually there seems also be example for checking From: -header
on sendmail distribution. It seach certaing strings from comment.)

/ Kari Hurtta

Kari Hurtta <hurtta@attruh.keh.iki.fi> writes:

> Sylvain Robitaille <syl@alcor.concordia.ca> writes:
>
> > Kari Hurtta wrote:
> >
> > > it is possible to write header check rulesets, which can reject mail.
> >
> > Alright, I stand corrected, but counter that what the OP wants, then, is
> > _easier_ to do with a milter ... :-)
>
> What questioner wants is bad idea.
>
> Anyway perhaps like that:
>
> LOCAL_RULESETS
> HFrom: $>CheckFrom
>
> SCheckFrom
> R $*@$=w $#error $: "553 I do not like your From header"
> R $*<$*@$=w> $#error $: "553 I do not like your From header"
>
> This do not catch all cases and is bad idea :-)
> Note that this ruleset ignores comments on From: -header.

And this is little too agressive :-)
It ignores also local mail ....

/ Kari Hurtta

Sylvain Robitaille <syl@alcor.concordia.ca> writes:

> Kari Hurtta wrote:
>
> > it is possible to write header check rulesets, which can reject mail.
>
> Alright, I stand corrected, but counter that what the OP wants, then, is
> _easier_ to do with a milter ... :-)

Perhaps. And anyway it is very bad idea.

LOCAL_RULESETS
HFrom: $>CheckFrom

SCheckFrom
R $*@$=w $@ $> CheckFromMatch
R $*<$*@$=w> $@ $> CheckFromMatch

SCheckFromMatch
R $* $&{client_name}
R $@ $@ OK
R $=w $@ OK
R $* $#error $: "553 I do not like your From: -header"