resolving email addresses

[Julian Field]

At 20:30 23/03/2004, you wrote:
>Okay, did the 'nslookup -t=MX realdomain'
>and received a series of Non-Authoritative responses and also used your
>recommendation and received multiple Authoritative answers.
>
>It appears the reverse lookup is working.  I wonder what is happening with
>sendmail?
>
>Also, I looked for Julian's suggestion to turn off
>'FEATURE(`relay_based_on_MX')dnl' at sendmail.org, but I couldn't find
>anything.

It's on http://www.sendmail.org/m4/features.html

>  If I remove this feature would anything else be lost?
>
>Thank you.
>
>James
>
>
>-----Original Message-----
>From: Derek Winkler [mailto:dwinkler at ALGORITHMICS.COM]
>Sent: Tuesday, March 23, 2004 12:08 PM
>To: MAILSCANNER at JISCMAIL.AC.UK
>Subject: Re: resolving email addresses
>
>
>This is what I'm thinking of, you're not using this...
>
>accept_unresolvable_domains:
>
>Normally, MAIL FROM: commands in the SMTP session will be refused if the
>host part of the argument to MAIL FROM: cannot be located in the host name
>service (e.g., an A or MX record in DNS). If you are inside a firewall that
>has only a limited view of the Internet host name space, this could cause
>problems. In this case you probably want to use this feature to accept all
>domains on input, even if they are unresolvable.
>
>Use nslookup...
>
># nslookup
>Default Server:  localhost
>Address:  127.0.0.1
>
> > set type=MX
> > realdomain.com
>Server:  localhost
>Address:  127.0.0.1
>
>Non-authoritative answer:
>realdomain.com  preference = 10, mail exchanger = mail.realdomain.com
>
>Authoritative answers can be found from:
>mail.realdomain.com     internet address = 192.216.19.101
> >
>
>Make sure you do it from the server.
>
> > -----Original Message-----
> > From: MailScanner mailing list [mailto:MAILSCANNER at JISCMAIL.AC.UK]On
> > Behalf Of James D. Parra
> > Sent: Tuesday, March 23, 2004 2:56 PM
> > To: MAILSCANNER at JISCMAIL.AC.UK
> > Subject: Re: resolving email addresses
> >
> >
> > Thanks Derek,
> >
> > How would I have the server find the MX records?
> >
> >
> > This is the forth MailScanner I built and previous three
> > didn't have that
> > error. Interesting though. I do see the Feature setting, I
> > think. Is this
> > it?
> > FEATURE(`relay_based_on_MX')dnl
> >
> > Thanks again for your help.
> >
> > James
> >
> >
> > -----Original Message-----
> > From: Derek Winkler [mailto:dwinkler at ALGORITHMICS.COM]
> > Sent: Tuesday, March 23, 2004 11:40 AM
> > To: MAILSCANNER at JISCMAIL.AC.UK
> > Subject: Re: resolving email addresses
> >
> >
> > > Hello,
> > >
> > > I tried to test a new MailScanner/Sendmail setup we have,
> > but from the
> > > outside a telnet session to the mail server will give an
> > > error of, "Domain
> > > of sender address "joesomebody at realdomain.com" doesn't
> > > resolve. However, I
> > > can ping the domain from the server.
> > >
> > > Any clues on how to fix this?
> >
> > You may have a feature of sendmail turned on which doesn't
> > accept email from
> > addresses which don't have MX records.
> >
> > Can the server find MX records for the domain?
> >
> > >
> > > Thank you in advance.
> > >
> > > James
> > >
> >

--
Julian Field
www.MailScanner.info
Professional Support Services at www.MailScanner.biz
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