Re: Newbie to Exchange needs MX record info

Thanks for the info.
I already have an 'A' record, it consists of @ and my IP address this works
fine for http, https and ftp access (with associated CNAME records)

For Exchange Mail 2003 As I understand It,
I create a 'Cname' record such as alias=mail , points to @ , ttl=3600
then the MX record
PRI=0, HOST=@

This will allow other mail handlers to deliver mail to Exchange using
anybody@xxxxxxxxxxxx (actual domain removed).)

Wil this also fix the problem of bounced outgoing mail, as apparently many
ISP's we send mail to apparently check to see if I am sending mail from a
legit domain?


Gary Demi
Software & Communication Concepts, Inc.
Microsoft Registered Partner
Houston, & Phoenix



"Al Mulnick" wrote:

> The help file that comes with Exchange would be appropriate. Search SMTP and
> or Internet.
>
> MX records are not "required" per se to deliver mail per RFC. However, it is
> a best practice to have one that designates the mail handler for your
> domain. This is accomplished by designating a host as a mail handler (MX is
> the designation for mail handler in DNS terms.)
>
> It is a best practice to designate a MX record that specifies a host by it's
> A record vs. any other type of record. During a SMTP transaction, the MTA
> (mail transfer agent) will receive a message. It will determine where to
> deliver that message and if it determines that message to be a remote MTA,
> it will then look at it's routing table to figure out if it knows how to
> contact that responsible MTA. If it doesn't have a specific route, it will
> then look to DNS and specifically will look for a MX record that specifies
> the mail handler for that domain (domain here is everything to the right of
> "@" in the address.) If an MX record does not exist, the MTA will look for
> an A record. If that doesn't exist, it will fail the delivery and return a
> non-delivery receipt (NDR). If an MX record does exist, it should reference
> an A record. Once that A record is discovered, it will be queried for it's
> IP address and a conversation will be started between the MTA's via the well
> known SMTP port, TCP 25. Messages will then be transferred and the recipient
> MTA will become responsible for the next step of delivery.
>
> Basically, that's how it works. Daniel Petri seems to have taken the time
> to explain it as well.
> http://www.petri.co.il/configure_mx_records_for_incoming_smtp_email_traffic.htm
>
> Having more than one MX record is done because the way SMTP mail works, it
> will try the lowest weighted (preferred) mail handler first. If it receives
> an error (depends on the error type), the sending MTA should then try to
> send to the next mailer listed. This provides some level of failure
> tolerance because you can have multiple hosts that receive mail for your
> domain. Should one be out of service, the other should pick up the slack.
> It's not a requirement.
>
> Typically, your ISP will offer queuing services. If your host should be
> down, they'll accept mail for your domain until you come back on-line at
> which time they'll dump the queued messages to your mailer. So in practice,
> you'll often see records that look like:
>
> yourdomain.net MX preference = 10, mail exchanger = smtp.yourdomain.net
> yourdomain.net MX preference = 50, mail exchanger = SMTP.yourISP.net
>
> Which would typically send mail destined for your domain to
> smtp.yourdomain.net. However, if that server were unavailable, a sending
> host would try to send the mail to the other server, SMTP.yourISP.net. When
> smtp.yourdomain.net came back into service, it would then receive the queued
> messages from the ISP MTA, SMTP.yourISP.net.
>
> One caveat to be aware of, is that some admins have configured their hosts
> to look for reverse DNS records as a way to reduce spam. I don't consider
> this effective, but that's my opinion. The reason I don't, is because I can
> have a sending host that is not also a receiving a host and therefore I
> wouldn't have a corresponding MX record. To have the sending and receiving
> host be the same, is more often done in smaller IT shops vs. the larger and
> global shops. By RFC, I am not required to have an MX record for a host that
> is sending only nor would I want to as there would be no path for that mail
> handler to ever deliver a message. A PTR record is a good idea for your
> sending host for the same reason. While not required, it is a good idea to
> more reliably transfer messages with your customers because some hosts are
> configured to check for a reverse lookup when receiving a message from your
> domain. Same goes with SPF records (you may want one); I don't spf records
> as effective nor desirable, but what do I know? ;)
>
>
> Does that help?
>
> Al
>
>
>
> "Gary Demi" <GaryDemi@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
> news:1067F097-FA48-4B5F-97D3-5F0957549B12@xxxxxxxxxxxxxxxx
> >I thought two MX records where required. The MX records should read
> >something
> > liklike mail.yourdomain.com or smtp.yourdomain.com (what prefix does
> > Exchange
> > use, and what help file are you referring to?
> >
> > Thanks
> > --
> > Gary Demi
> > Software & Communication Concepts, Inc.
> > Microsoft Registered Partner
> > Houston, & Phoenix
> >
> >
> >
> > "Al Mulnick" wrote:
> >
> >> Two MX resource records?
> >>
> >> MX resource records are used to designate mail handlers for your domain.
> >> The A RR is the host name, and the MX references the A.
> >>
> >> If you have the A already, you would have your lowest priority MX record
> >> specify the A record as the mail handler. You may also want a reverse
> >> PTR
> >> (some domains check this record when receiving mail from you), but that's
> >> up
> >> to you. The higher priority record, if you specify one, would typically
> >> be
> >> for a backup mail handler such as might be provided by your ISP.
> >>
> >> Check out the help files for more information regarding MX and A records
> >> and
> >> how to set this up. I believe it has mail flow pictures in there if
> >> that's
> >> helpful.
> >>
> >> Al
> >>
> >>
> >> "Gary Demi" <GaryDemi@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
> >> news:9DEFC442-1929-4252-A261-BE4FFCA4A901@xxxxxxxxxxxxxxxx
> >> > We are running SBS2003 premium and starting to use exchange. Right now
> >> > we
> >> > are
> >> > running one NIC behind a NAT router.
> >> >
> >> > We have access to the DNS records on out nameserver through ouw domain
> >> > registrar.
> >> >
> >> > We have a public domain name pointing to the SBS2003 computer (via the
> >> > A
> >> > record). To what URL do we point the two MX records (pri=0 & pri-10)
> >> > so
> >> > that
> >> > Exchange Server is recognized as a mail server.
> >> >
> >> > A link to the the appropriate setup docs would be nice.
> >> > --
> >> > Gary Demi
> >> > Software & Communication Concepts, Inc.
> >> > Microsoft Registered Partner
> >> > Houston, & Phoenix
> >> >
> >>
> >>
> >>
>
>
>
.

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