>From experience: the RFC and real life are a bit off. with out an MX
record exchange will look at the root of your FQDN, so it will look at
durr-usa.com and see that IP. It will not go any deeper to a machine
name. Just add an MX record and solve the problem.

--Kevinm M, WLKMMAS, UCC+WCA, And Beyond
Did I just say that out loud?


-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED]] On Behalf Of Joe Pochedley
Sent: Wednesday, March 13, 2002 10:16 AM
To: Exchange Discussions
Cc: '[EMAIL PROTECTED]'
Subject: RE: Network Error During Host Resolution


They shouldn't need an actual MX record if they have an A record.....
(I know it's proper to have an MX record, but it's not absolutely
necessary.....)  Since de.durr-usa.com DOES have an A record, Exchange
SMTP SHOULD be able to locate it....

>From RFC 2821

Section 3.6

3.6 Domains

   Only resolvable, fully-qualified, domain names (FQDNs) are permitted
   when domain names are used in SMTP.  In other words, names that can
   be resolved to MX RRs or A RRs (as discussed in section 5) are
   permitted, as are CNAME RRs whose targets can be resolved, in turn,
   to MX or A RRs.  Local nicknames or unqualified names MUST NOT be
   used.  There are two exceptions to the rule requiring FQDNs:

   -  The domain name given in the EHLO command MUST BE either a primary
      host name (a domain name that resolves to an A RR) or, if the host
      has no name, an address literal as described in section 4.1.1.1.

   -  The reserved mailbox name "postmaster" may be used in a RCPT
      command without domain qualification (see section 4.1.1.3) and
      MUST be accepted if so used.

>From Section 5

   Once an SMTP client lexically identifies a domain to which mail will
   be delivered for processing (as described in sections 3.6 and 3.7), a
   DNS lookup MUST be performed to resolve the domain name [22].  The
   names are expected to be fully-qualified domain names (FQDNs):
   mechanisms for inferring FQDNs from partial names or local aliases
   are outside of this specification and, due to a history of problems,
   are generally discouraged.  The lookup first attempts to locate an MX
   record associated with the name.  If a CNAME record is found instead,
   the resulting name is processed as if it were the initial name.  If
   no MX records are found, but an A RR is found, the A RR is treated as
   if it was associated with an implicit MX RR, with a preference of 0,
   pointing to that host.  If one or more MX RRs are found for a given
   name, SMTP systems MUST NOT utilize any A RRs associated with that
   name unless they are located using the MX RRs; the "implicit MX" rule
   above applies only if there are no MX records present.  If MX records
   are present, but none of them are usable, this situation MUST be
   reported as an error.

Still Looking........

Joe Pochedley
"I like deadlines," 
cartoonist Scott Adams once said. 
"I especially like the whooshing 
sound they make as they fly by."




-----Original Message-----
From: Roger Seielstad [mailto:[EMAIL PROTECTED]] 
Sent: Wednesday, March 13, 2002 12:56 PM
To: Exchange Discussions
Subject: RE: Network Error During Host Resolution


They don't have an MX record, so you can't find a server to which you
can deliver mail:

bash-2.04$ dig de.durr-usa.com mx

; <<>> DiG 9.1.2 <<>> de.durr-usa.com mx
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 37004
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0

;; QUESTION SECTION:
;de.durr-usa.com.               IN      MX

;; AUTHORITY SECTION:
durr-usa.com.           7200    IN      SOA     ns1.ameritech.net.
postmaster.ameritech.net. 200111271 3600 900 604800 7200

;; Query time: 361 msec
;; SERVER: 66.92.212.61#53(66.92.212.61)
;; WHEN: Wed Mar 13 12:52:37 2002
;; MSG SIZE  rcvd: 97



------------------------------------------------------
Roger D. Seielstad - MCSE
Sr. Systems Administrator
Peregrine Systems
Atlanta, GA


> -----Original Message-----
> From: Joe Pochedley [mailto:[EMAIL PROTECTED]]
> Sent: Wednesday, March 13, 2002 11:40 AM
> To: Exchange Discussions
> Subject: Network Error During Host Resolution
> 
> 
> Kind ladies and gentlemen of the list.  I am sending this message 
> again in hopes that someone will be able to help me.
> I'm not intending to spam the list, just looking for some 
> assistance.  I've heard from a few people off list that 
> they've also experienced similar problems, but none of them 
> have / had a solution and were hoping that I had found 
> something with yesterday's inquiry.......
> 
> If anyone out there can help, or at least give me another direction to

> explore I would greatly appreciate it.  (I know about MS PSS and it is

> my final option, but I'd rather not go there).
> 
> My Exchange Server is v5.5 SP4
> 
> Problem is as follows:
> 
> -Begin Quoted Error Message-
>  
> Your message did not reach some or all of the intended recipients.
> 
>       Subject:        RE: Durr Industries 
>       Sent:   3/10/02 1:11 PM
> 
> The following recipient(s) could not be reached:
> 
>       '[EMAIL PROTECTED]' on 3/12/02 1:01 PM
>             The recipient name is not recognized
>       The MTS-ID of the original message is: c=US;a= 
> ;p=namfg;l=SEQUOYAH-020310181103Z-71
>             MSEXCH:IMS:namfg:cleveland:SEQUOYAH 3499
> (000B09AA) network error during host resolution
> 
>       [EMAIL PROTECTED] on 3/12/02 1:01 PM
>             The recipient name is not recognized
>       The MTS-ID of the original message is: c=US;a= 
> ;p=namfg;l=SEQUOYAH-020310181103Z-71
>             MSEXCH:IMS:namfg:cleveland:SEQUOYAH 3499
> (000B09AA) network error during host resolution
> 
> -End Quoted Error Message-
> 
> I'm getting this error when trying to send to de.durr-usa.com, and 
> have in the past had this error on a few other addresses, but the 
> message has always eventually gone through in the past.  This time 
> though, I can't get anything to go through to de.durr-usa.com.  
> Supposedly, we have been able to send to these recipients in the past,

> but it's only been in the past two months that there have been any 
> problems that the end user has complained about...  No changes have
> been made to our Exchange Server or DNS servers for at least 
> the past 4-6 months.
> 
> I am able to look up de.durr-usa.com using the same DNS server that 
> the exchange server is using, so it's not that the DNS server can't 
> resolve the host name...  I looked up durr-usa.com's DNS records and 
> there is no MX record for the sub domain 'de' but there is an A 
> record, so theoretically the Exchange SMTP service should use the A 
> record in place of the MX record, correct?
> 
> I am at a loss.
> 
> Thanks in advance.
> 
> Joe Pochedley
> 
> 
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