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date: Wed, 16 Apr 2008 14:16:02 -0700,
group: microsoft.public.exchange.misc
back
email routing
not sure if this is exch related but here is odd issue we facing, 2 different
people within our organization reported recently same issue where someone
from external domain is sending email to us, this email has also multiple
recipients with different email domain essentially is email to many people
from different organizations. This email is bounced back to sender notifying
sender message was not delivered to following recipients and is listing
recipients from our domain. sender is forwarding same message again this time
there is only one recipient or 2 those who did not get initial email and this
time no problem email goes thru fine.
odd things is we have this issue (so far) with 2 different domain so it is
not isolated to one domain, original email sent from those domains never hit
our receiving server, we requested email server logs from IT at other domain
for those failures and weird thing is their email is trying to be sent to
public IP address of our website which obviously is different then our mail
servers IPs accepting external email so one would thing we have MX records
incorrectly configured. They are configured correctly have MX, A and PTR
records for 3 different mail servers neither of this IPs is our public
website IP, additionally IP address assigned to our public website never was
in past assigned to mail server, never ever so it is not cached. we can
connect from commend line to several different publicly available DNS servers
and nslookup mx records for our domain all is good, making this story short,
how it is possible those again 2 different domains' exch servers are sending
email to our domain to wrong IP address????! and again it only appears to be
an issue if they are sending to group of people no problem when sending to
individuals. Finally as last addition our public website has obviously A
record and we also added PTR since this one of the forms on our website is
sending outgoing confirmation messages but it is not configured to accept
messages nor have MX record... any ideas?
date: Wed, 16 Apr 2008 14:16:02 -0700
author: RW
Re: email routing
Read your own post and see if you don't agree with me that it's practically
impossible to comprehend. Having said that, I gather that you have three MX
records. I suggest that you telnet into port 25 of each the hosts
corresponding to each and verify that they will accept mail for the
recipients in question.
--
Ed Crowley
MVP - Exchange
"Protecting the world from PSTs and brick backups!"
"RW" wrote in message
news:198751ED-C236-45C5-BFDE-90BFD091D778@microsoft.com...
> not sure if this is exch related but here is odd issue we facing, 2
> different
> people within our organization reported recently same issue where someone
> from external domain is sending email to us, this email has also multiple
> recipients with different email domain essentially is email to many people
> from different organizations. This email is bounced back to sender
> notifying
> sender message was not delivered to following recipients and is listing
> recipients from our domain. sender is forwarding same message again this
> time
> there is only one recipient or 2 those who did not get initial email and
> this
> time no problem email goes thru fine.
> odd things is we have this issue (so far) with 2 different domain so it is
> not isolated to one domain, original email sent from those domains never
> hit
> our receiving server, we requested email server logs from IT at other
> domain
> for those failures and weird thing is their email is trying to be sent to
> public IP address of our website which obviously is different then our
> mail
> servers IPs accepting external email so one would thing we have MX records
> incorrectly configured. They are configured correctly have MX, A and PTR
> records for 3 different mail servers neither of this IPs is our public
> website IP, additionally IP address assigned to our public website never
> was
> in past assigned to mail server, never ever so it is not cached. we can
> connect from commend line to several different publicly available DNS
> servers
> and nslookup mx records for our domain all is good, making this story
> short,
> how it is possible those again 2 different domains' exch servers are
> sending
> email to our domain to wrong IP address????! and again it only appears to
> be
> an issue if they are sending to group of people no problem when sending to
> individuals. Finally as last addition our public website has obviously A
> record and we also added PTR since this one of the forms on our website is
> sending outgoing confirmation messages but it is not configured to accept
> messages nor have MX record... any ideas?
date: Fri, 18 Apr 2008 21:55:23 -0700
author: Ed Crowley [MVP]
Re: email routing
I try to make it short and clear:
- Yes, we do have 3 MX records and all of them are accessible - there is no
problem here
- problem is that we had so far 2 instances where email from external domain
(2 different domains) sent to us was bounced to original receipient, when we
as the other end domain to involved their IT as we cannot troubleshoot their
end problem (to some extend only) they discovered that their exchange server
was trying to do smtp conection to our public website IP
- our public website IP is different then our MX IPs, this particular IP
they were trying to connect never had MX record for our domain
does this make more sense? basicaly their mail server is trying to exchange
email with our public webserver.
if this is still not clear here it is again
IP 1 - has MX, A and PTR record - mail server
IP 2 - has MX, A and PTR record - mail server
IP 3 - has MX, A and PTR record - mail server
IP 4 - has A and PTR record - web server
2 different domains recently had instances where their exchs were trying to
send email to our webserver (IP4) how??! there is no MX record. Those orgs IT
also confirmed that if they do nslookup for our domain MX records, there is
no IP4 listed anywhere... odd part is that in both of this instances email
was orginally sent to group of people and bounced back as NDR only for our
domain, sender then forward same message this time only to receipients from
our domain and all works ok!
I would say it is DNS issue but how this is possible? where their exch
server is getting this from and again we never ever had MX for this IP
address (IP4 webserver)
"Ed Crowley [MVP]" wrote:
> Read your own post and see if you don't agree with me that it's practically
> impossible to comprehend. Having said that, I gather that you have three MX
> records. I suggest that you telnet into port 25 of each the hosts
> corresponding to each and verify that they will accept mail for the
> recipients in question.
> --
> Ed Crowley
> MVP - Exchange
> "Protecting the world from PSTs and brick backups!"
>
> "RW" wrote in message
> news:198751ED-C236-45C5-BFDE-90BFD091D778@microsoft.com...
> > not sure if this is exch related but here is odd issue we facing, 2
> > different
> > people within our organization reported recently same issue where someone
> > from external domain is sending email to us, this email has also multiple
> > recipients with different email domain essentially is email to many people
> > from different organizations. This email is bounced back to sender
> > notifying
> > sender message was not delivered to following recipients and is listing
> > recipients from our domain. sender is forwarding same message again this
> > time
> > there is only one recipient or 2 those who did not get initial email and
> > this
> > time no problem email goes thru fine.
> > odd things is we have this issue (so far) with 2 different domain so it is
> > not isolated to one domain, original email sent from those domains never
> > hit
> > our receiving server, we requested email server logs from IT at other
> > domain
> > for those failures and weird thing is their email is trying to be sent to
> > public IP address of our website which obviously is different then our
> > mail
> > servers IPs accepting external email so one would thing we have MX records
> > incorrectly configured. They are configured correctly have MX, A and PTR
> > records for 3 different mail servers neither of this IPs is our public
> > website IP, additionally IP address assigned to our public website never
> > was
> > in past assigned to mail server, never ever so it is not cached. we can
> > connect from commend line to several different publicly available DNS
> > servers
> > and nslookup mx records for our domain all is good, making this story
> > short,
> > how it is possible those again 2 different domains' exch servers are
> > sending
> > email to our domain to wrong IP address????! and again it only appears to
> > be
> > an issue if they are sending to group of people no problem when sending to
> > individuals. Finally as last addition our public website has obviously A
> > record and we also added PTR since this one of the forms on our website is
> > sending outgoing confirmation messages but it is not configured to accept
> > messages nor have MX record... any ideas?
>
>
>
date: Sat, 19 Apr 2008 06:23:00 -0700
author: RW
Re: email routing
I can't say based on your description. Post your domain name and I can do
an NSLOOKUP and maybe give you a better idea.
--
Ed Crowley
MVP - Exchange
"Protecting the world from PSTs and brick backups!"
"RW" wrote in message
news:8B8EA769-AE8D-4357-B3E4-E8CB21A993B2@microsoft.com...
>I try to make it short and clear:
> - Yes, we do have 3 MX records and all of them are accessible - there is
> no
> problem here
> - problem is that we had so far 2 instances where email from external
> domain
> (2 different domains) sent to us was bounced to original receipient, when
> we
> as the other end domain to involved their IT as we cannot troubleshoot
> their
> end problem (to some extend only) they discovered that their exchange
> server
> was trying to do smtp conection to our public website IP
> - our public website IP is different then our MX IPs, this particular IP
> they were trying to connect never had MX record for our domain
>
> does this make more sense? basicaly their mail server is trying to
> exchange
> email with our public webserver.
>
> if this is still not clear here it is again
>
> IP 1 - has MX, A and PTR record - mail server
> IP 2 - has MX, A and PTR record - mail server
> IP 3 - has MX, A and PTR record - mail server
> IP 4 - has A and PTR record - web server
>
>
> 2 different domains recently had instances where their exchs were trying
> to
> send email to our webserver (IP4) how??! there is no MX record. Those orgs
> IT
> also confirmed that if they do nslookup for our domain MX records, there
> is
> no IP4 listed anywhere... odd part is that in both of this instances email
> was orginally sent to group of people and bounced back as NDR only for our
> domain, sender then forward same message this time only to receipients
> from
> our domain and all works ok!
>
> I would say it is DNS issue but how this is possible? where their exch
> server is getting this from and again we never ever had MX for this IP
> address (IP4 webserver)
>
>
>
> "Ed Crowley [MVP]" wrote:
>
>> Read your own post and see if you don't agree with me that it's
>> practically
>> impossible to comprehend. Having said that, I gather that you have three
>> MX
>> records. I suggest that you telnet into port 25 of each the hosts
>> corresponding to each and verify that they will accept mail for the
>> recipients in question.
>> --
>> Ed Crowley
>> MVP - Exchange
>> "Protecting the world from PSTs and brick backups!"
>>
>> "RW" wrote in message
>> news:198751ED-C236-45C5-BFDE-90BFD091D778@microsoft.com...
>> > not sure if this is exch related but here is odd issue we facing, 2
>> > different
>> > people within our organization reported recently same issue where
>> > someone
>> > from external domain is sending email to us, this email has also
>> > multiple
>> > recipients with different email domain essentially is email to many
>> > people
>> > from different organizations. This email is bounced back to sender
>> > notifying
>> > sender message was not delivered to following recipients and is listing
>> > recipients from our domain. sender is forwarding same message again
>> > this
>> > time
>> > there is only one recipient or 2 those who did not get initial email
>> > and
>> > this
>> > time no problem email goes thru fine.
>> > odd things is we have this issue (so far) with 2 different domain so it
>> > is
>> > not isolated to one domain, original email sent from those domains
>> > never
>> > hit
>> > our receiving server, we requested email server logs from IT at other
>> > domain
>> > for those failures and weird thing is their email is trying to be sent
>> > to
>> > public IP address of our website which obviously is different then our
>> > mail
>> > servers IPs accepting external email so one would thing we have MX
>> > records
>> > incorrectly configured. They are configured correctly have MX, A and
>> > PTR
>> > records for 3 different mail servers neither of this IPs is our public
>> > website IP, additionally IP address assigned to our public website
>> > never
>> > was
>> > in past assigned to mail server, never ever so it is not cached. we can
>> > connect from commend line to several different publicly available DNS
>> > servers
>> > and nslookup mx records for our domain all is good, making this story
>> > short,
>> > how it is possible those again 2 different domains' exch servers are
>> > sending
>> > email to our domain to wrong IP address????! and again it only appears
>> > to
>> > be
>> > an issue if they are sending to group of people no problem when sending
>> > to
>> > individuals. Finally as last addition our public website has obviously
>> > A
>> > record and we also added PTR since this one of the forms on our website
>> > is
>> > sending outgoing confirmation messages but it is not configured to
>> > accept
>> > messages nor have MX record... any ideas?
>>
>>
>>
date: Mon, 5 May 2008 18:21:57 -0700
author: Ed Crowley [MVP]
Re: email routing
Thanks for you offer but I can do nslokup myself, if this would be that
simple I would not post this question here since I know our MX, A, etc
records are defined correctly.. in any event here is an explenation of why we
have had this problem, from blog at easydns.com:
"...email originating on the Bell Canada, Bellnexxia network is sporadically
being delivered to the domain name's A record instead of the designated MX
record.."
http://blog.easydns.org/archives/206-Bell-Canada-Bellnexxia-mail-delivery-problems-return.html
"Ed Crowley [MVP]" wrote:
> I can't say based on your description. Post your domain name and I can do
> an NSLOOKUP and maybe give you a better idea.
> --
> Ed Crowley
> MVP - Exchange
> "Protecting the world from PSTs and brick backups!"
>
> "RW" wrote in message
> news:8B8EA769-AE8D-4357-B3E4-E8CB21A993B2@microsoft.com...
> >I try to make it short and clear:
> > - Yes, we do have 3 MX records and all of them are accessible - there is
> > no
> > problem here
> > - problem is that we had so far 2 instances where email from external
> > domain
> > (2 different domains) sent to us was bounced to original receipient, when
> > we
> > as the other end domain to involved their IT as we cannot troubleshoot
> > their
> > end problem (to some extend only) they discovered that their exchange
> > server
> > was trying to do smtp conection to our public website IP
> > - our public website IP is different then our MX IPs, this particular IP
> > they were trying to connect never had MX record for our domain
> >
> > does this make more sense? basicaly their mail server is trying to
> > exchange
> > email with our public webserver.
> >
> > if this is still not clear here it is again
> >
> > IP 1 - has MX, A and PTR record - mail server
> > IP 2 - has MX, A and PTR record - mail server
> > IP 3 - has MX, A and PTR record - mail server
> > IP 4 - has A and PTR record - web server
> >
> >
> > 2 different domains recently had instances where their exchs were trying
> > to
> > send email to our webserver (IP4) how??! there is no MX record. Those orgs
> > IT
> > also confirmed that if they do nslookup for our domain MX records, there
> > is
> > no IP4 listed anywhere... odd part is that in both of this instances email
> > was orginally sent to group of people and bounced back as NDR only for our
> > domain, sender then forward same message this time only to receipients
> > from
> > our domain and all works ok!
> >
> > I would say it is DNS issue but how this is possible? where their exch
> > server is getting this from and again we never ever had MX for this IP
> > address (IP4 webserver)
> >
> >
> >
> > "Ed Crowley [MVP]" wrote:
> >
> >> Read your own post and see if you don't agree with me that it's
> >> practically
> >> impossible to comprehend. Having said that, I gather that you have three
> >> MX
> >> records. I suggest that you telnet into port 25 of each the hosts
> >> corresponding to each and verify that they will accept mail for the
> >> recipients in question.
> >> --
> >> Ed Crowley
> >> MVP - Exchange
> >> "Protecting the world from PSTs and brick backups!"
> >>
> >> "RW" wrote in message
> >> news:198751ED-C236-45C5-BFDE-90BFD091D778@microsoft.com...
> >> > not sure if this is exch related but here is odd issue we facing, 2
> >> > different
> >> > people within our organization reported recently same issue where
> >> > someone
> >> > from external domain is sending email to us, this email has also
> >> > multiple
> >> > recipients with different email domain essentially is email to many
> >> > people
> >> > from different organizations. This email is bounced back to sender
> >> > notifying
> >> > sender message was not delivered to following recipients and is listing
> >> > recipients from our domain. sender is forwarding same message again
> >> > this
> >> > time
> >> > there is only one recipient or 2 those who did not get initial email
> >> > and
> >> > this
> >> > time no problem email goes thru fine.
> >> > odd things is we have this issue (so far) with 2 different domain so it
> >> > is
> >> > not isolated to one domain, original email sent from those domains
> >> > never
> >> > hit
> >> > our receiving server, we requested email server logs from IT at other
> >> > domain
> >> > for those failures and weird thing is their email is trying to be sent
> >> > to
> >> > public IP address of our website which obviously is different then our
> >> > mail
> >> > servers IPs accepting external email so one would thing we have MX
> >> > records
> >> > incorrectly configured. They are configured correctly have MX, A and
> >> > PTR
> >> > records for 3 different mail servers neither of this IPs is our public
> >> > website IP, additionally IP address assigned to our public website
> >> > never
> >> > was
> >> > in past assigned to mail server, never ever so it is not cached. we can
> >> > connect from commend line to several different publicly available DNS
> >> > servers
> >> > and nslookup mx records for our domain all is good, making this story
> >> > short,
> >> > how it is possible those again 2 different domains' exch servers are
> >> > sending
> >> > email to our domain to wrong IP address????! and again it only appears
> >> > to
> >> > be
> >> > an issue if they are sending to group of people no problem when sending
> >> > to
> >> > individuals. Finally as last addition our public website has obviously
> >> > A
> >> > record and we also added PTR since this one of the forms on our website
> >> > is
> >> > sending outgoing confirmation messages but it is not configured to
> >> > accept
> >> > messages nor have MX record... any ideas?
> >>
> >>
> >>
>
>
>
date: Tue, 6 May 2008 17:09:00 -0700
author: RW
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