• RSS
  • Twitter
  • FaceBook

Exchange Server Forums

Forums | Register | Login | My Profile | Inbox | RSS RSS icon | My Subscription | My Forums | Address Book | Member List | Search | FAQ | Ticket List | Log Out

Delayed or rejected email to certain domains

Users viewing this topic: none

Logged in as: Guest
  Printable Version
All Forums >> [Microsoft Exchange 2003] >> Exchange 2003 SBS >> Delayed or rejected email to certain domains Page: [1]
Login
Message << Older Topic   Newer Topic >>
Delayed or rejected email to certain domains - 2.Feb.2010 1:15:19 AM   
Gwire

 

Posts: 4
Joined: 4.Feb.2006
Status: offline
Mail server is SBS 2003 SP2 exchange 2003 SP1 static IP
Currently all email outgoing is straight from server to internet, no smarthost etc….or smtp connector. ISP is ATT with SSL required.
No internet issues and I am receiving emails fine. Once again having issues sending email to certain domains.
It is either delayed 4.4.7 or Refused - Please relay through your ISP mail server HOST so forth.

Server is only used as mail server no web hosting. Website of domain hosted elswhere domainname.com, but incoming email name@domainname.com comes into server on location after going through filters at psmtp.com.

The smtp virtual server setting under FQDN does not list the domainname.com but the internal.name.local listing.
I am thinking that these domains I am having issues with are doing a reverse domain lookup and it does not see FQDN, but instead my internal.name.local name. ATT has suggested to create a PTR record to point to my Static IP address of mail server, will I still need to associate my static IP with my domainname.com? Will this effect my website that is already associated with another IP address elswhere? What exactly should I ask for when requesting PTR if I need this?
Thanks for your help, I am new to this DNS configurations that is why moving cautiously.
Post #: 1
RE: Delayed or rejected email to certain domains - 2.Feb.2010 9:45:56 AM   
uemurad

 

Posts: 8232
Joined: 7.Jan.2004
From: California, USA
Status: offline
First, a little DNS review.  There are several different types of DNS records.  The ones you are talking about are "A" and "PTR" records.  One associates an IP address to a FQDN, the other associates a FQDN to an IP address.  While they may sound the same, they are not.  The difference is in the information you provide and what is returned.

When you query DNS and supply a FQDN, the DNS server looks up the A records for a match.  If it finds one, it returns an IP address.

When you query DNS and supply an IP address, the DNS server looks up the PTR records for a match.  If it finds one, it returns a FQDN.  This is often called a reverse lookup, or RDNS query.

Note:  The FQDN does not have to be the same in the A and PTR records for the same IP address.

Some mail systems perform a RDNS query when an outside system opens an SMTP session.  The IP address of the sending system is known because it is embedded in the TCP packets being sent.  The recipient system takes that IP address and queries DNS to obtain the FQDN.  In other words, it performs a RDNS query meaning it asks for the FQDN based on the IP address which means DNS will search the PTR records.  This is considered to be a reliable method of discovering the identity of the sender because the public DNS is supposed to be impervious to forgery.

The actions that a mail system can take can vary.  If no FQDN is returned - meaning there is no PTR record - many systems will terminate the SMTP session.  Some systems may compare the domain name in the FQDN to the domain name in the HELO/EHLO command.  Some may compare the FQDN to the sending SMTP address (MAIL FROM command).

What you want to tell your ISP (or whoever hosts your DNS records) is that you want a PTR record for the IP address from which your outbound mail enters the Internet, and you give them a FQDN to associate with it.  Presumably you'd want to choose a FQDN that includes your registered domain name you use for your Email addresses (e.g. outboundmail.mydomain.com if your Email addresses are first.last@mydomain.com).

_____________________________

Regards,

Dean T. Uemura
Microsoft MVP - Exchange (2007-2011)
exchangeguy.blogspot.com
uemurad@yahoo.com

(in reply to Gwire)
Post #: 2
RE: Delayed or rejected email to certain domains - 2.Feb.2010 11:29:37 AM   
Gwire

 

Posts: 4
Joined: 4.Feb.2006
Status: offline
Thanks for the fast reply and info....

If I supply ISP with the IP address from which my outbound mail enters the internet (My static IP from office) and I give them my registered domain name will this in any way affect my emails sent to my domain name through psmtp.com filters or our website hosted elswhere associated with this same registered domain name?

Will I need to change the SMTP virtual Server\advance delivery tab FQDN to the registered domain name instead of the XXXXX.XXXX.local indicated now?
Do I need to add some external DNS IP's in the same tab, indicating (configure external dns)

Thanks for the info once again.

Gilbert

(in reply to uemurad)
Post #: 3
RE: Delayed or rejected email to certain domains - 4.Feb.2010 12:30:26 PM   
Gwire

 

Posts: 4
Joined: 4.Feb.2006
Status: offline
Update,
My MX record indicates (mydomain.com.s7a1.psmtp.com) when I do a look up.
When requesting a PTR to my static IP address, Do I specifi only mydomain.com or mail.mydomain.com or exactly as indicated above to match mx record?
And do I change the SMTP virtual server SMTP Banner to what I have selected for PTR.

Thanks
Gilbert

(in reply to Gwire)
Post #: 4

Page:   [1] << Older Topic    Newer Topic >>
All Forums >> [Microsoft Exchange 2003] >> Exchange 2003 SBS >> Delayed or rejected email to certain domains Page: [1]
Jump to:

New Messages No New Messages
Hot Topic w/ New Messages Hot Topic w/o New Messages
Locked w/ New Messages Locked w/o New Messages
 Post New Thread
 Reply to Message
 Post New Poll
 Submit Vote
 Delete My Own Post
 Delete My Own Thread
 Rate Posts


Follow TechGenix on Twitter