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wobble_wobble

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Reply with quote  #16 
Quote:
Originally Posted by smac693

...

Are you saying that IIS 8 corrects the problem?  My server is Windows 2008 R2, so it has IIS 7.5.

...

No.
There is a bug feature in IIS 6 related to what you speak of. This was fixed in IIS8 with regard servers with multiple websites and multiple listening IP addresses and the responding traffic. But no, never fixed on IIS 6, the service that gives us SMTP.

So no change will fix the issue and you need a work around.


Quote:

PS.  My question remains:  what file is being accessed to pull the IP address inserted into the bracket?  If IIS 8 corrects the above problem, then I will look into purchasing a Windows 2012 server machine.

No file - the IP address set on the NIC.

Message me offline and send me a mail header and the IPconfig and a screen dump of the IIS config.


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donoli

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Reply with quote  #17 
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No file - the IP address set on the NIC.


I said that yesterday in post #13.
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cj_berlin

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Reply with quote  #18 
Guys,

The line in the mail header is being inserted by the *receiving* SMTP server so the only way to influence this from the sending end is by making sure it actually uses that address to initiate the communications.

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donoli

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Reply with quote  #19 
I said that too in post #13.
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smac693

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Reply with quote  #20 
cj_berlin:

How do I make sure it actually uses that address to initiate communications?
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smac693

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Reply with quote  #21 
donoli wrote: " At that point, the X-Originating IP in the headers is the external IP that's read by the incoming server, that is the receiving server."

Two questions: 

1.  What program is doing the reading?

2.  What file is the program reading?


The route table?

As a test, I added a new, unused static IP to the first GUI screen of the NIC.  I unplugged the cable.  I sent a message.  The header of the email contained the unused static IP BEFORE it was sent (it could not be sent because I had unplugged the cable.)

So, some program is reading a table and inserting the wrong IP address.

Windows Server 2012 does not seem to correct this, because SMTP Server uses IIS 6.
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cj_berlin

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Reply with quote  #22 
Quote:
Originally Posted by smac693
cj_berlin:

How do I make sure it actually uses that address to initiate communications?


By setting it as default on a NIC. However, https://blogs.technet.microsoft.com/networking/2009/04/24/source-ip-address-selection-on-a-multi-homed-windows-computer/ seems to state that of multiple addresses from the same subnet the one closest to the gateway (i.e. that with the longest matching prefix) will be chosen. Since you have not disclosed your IPs and that of your Default Gateway, I cannot provide any advice here.

I understand that you only have one NIC in the server, but if you could upgrade to Server 2012 you could enable the Hyper-V Role (without actually virtualising anything) and use the virtual switch facility to create multiple host interfaces.

Alternatively, you could set your "outbound mail" IP as default and use the secondary (listening) IPs for services that do not need this kind of binding.

Alternatively, you could virtualise the web/mail server and give it multiple vNICs to separate the IP addresses. Again, check your actual IPs for the matching prefix length.

You could also try another mail server, something along the lines of MailEnable. However, I am not sure if this would definitely resolve your issue, depends on how the product works.

Lastly, you could set up the "outbound mail" IP on a separate machine (which need not run Windows and could easily be a VM) and use it as a SMTP relay for your comms.

FWIW,

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cj_berlin

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Reply with quote  #23 
Quote:
Originally Posted by smac693

2.  What file is the program reading?


The IIS metabase.

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donoli

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Reply with quote  #24 
Quote:
donoli wrote: " At that point, the X-Originating IP in the headers is the external IP that's read by the incoming server, that is the receiving server."

Two questions: 

1.  What program is doing the reading?

2.  What file is the program reading? 



There is no file & no program. The NIC on the receiving server is reading the TCP/IP syn packets from your SMTP server & answers with an ACK packet. It's in the NIC's source code &/or drivers.
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KingAlPal

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Reply with quote  #25 
Received: from mta..com ([123.456.789.1])
    by sys.comcast.net with comcast id XX1ZZ2YY3

That part of the header is added by the receiving server (sys.comcast.net), is it not? That server is simply saying what IP address the incoming connection was coming from.


[...which is what donoli said! Don't know why donoli's reply wasn't showing when I read through the thread... [biggrin] ]
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