SMTP outgoing IP address

Posted on 2006-06-09
Last Modified: 2008-02-01

I am using IIS vSMTP for sending mail.  

My server has 3 IP addresses on one NIC.

I want to specify which IP address vSMTP should use when it makes it's outgoing connections....anyway to do this?
Question by:thomp361
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LVL 34

Accepted Solution

Dave_Dietz earned 250 total points
ID: 16872813
I believe the SMTP service will simply use the first IP address in the binding order to make outbound connections.

Try shifting the binding order and see if that helps.

Dave Dietz

Assisted Solution

shambhusingh2004 earned 250 total points
ID: 16875825
Yes,You can use/blind other IP in local SMTP to send mails.

Go to IIS.
Select default SMTP virtual server properties.
Select IP address to which you want to use.
The go the Access TAB
Then select relay restration option
ADD IP address.

Warm Regards,

Vipin Gupta


Author Comment

ID: 16877077
Hi Vipin,

My IP addresses are *.81, *.84, *.85

My server uses .81 for outgoing connections but I want vSMTP to use .85 for outgoing connections.

I tried your idea of adding a relay restriction option, I selected .85, and I granted relay to .85

However, when emails get sent they still have .81 in, so it seems that the vSMTP is still using .81 for outgoing connections.

Thanks for the help,
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Author Comment

ID: 16877092
Hi Dave,

I changed the IP order in the NIC but the box (and vSMTP) still seems to use .81 for outgoing connections....I thought at first that might have done it but it hasn't.

Expert Comment

ID: 16877119
Hi Marc -

I have production server on which mails are relaying from second IP of server.I have following configuration,please confirm with your server configuration :

My SQL IP are : (Primery) (Secondary)

>> Go to IIS :
>> General TAB >> Assigned IP '' & advanced tab >> add IP ''  & port 25.
>> Access TAB
>> Relay tab >> Only the list below >> add IP ''
>> Allow all computers which successfully authenication to relay,regarding above list (check mark)

Warm Regards,

Vipin Gupta


Author Comment

ID: 16877185
Hi Vipin,

That's what I tried to do, setup a relay for .85, but the when email's get sent they still have .81 in the header.

To confirm, I selected .85 on the 'General' tab, then on the 'Access' tab -> relay restrictions -> 'only the list below' -> granted .85

LVL 34

Expert Comment

ID: 16879192
How did you change the order of the IP addresses?

I believe SMTP will use the one that shows up as the first on the list.

Did you restart the service after making the change?

Dave Dietz

Author Comment

ID: 16885567
I changed the order in the NIC settings under "ip addresses" ...turns out that my server provider said I can only use on of my three IP for outgoing connections anways, so getting vSMTP to use a different IP is a moot point now.

Thanks for helping guys, I'll split the points.

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