Website emails rejected when using relay.plus.net.

[#1]

I'm running a community groups website.

There is a page for users to sign up to our email list. Obviously it sends out a confirmation email with a link to click.

If the emails are sent directly from the server (a VPS running windows and mercury mail as the MTA) then emails go through to google with no worries but emails to yahoo are not delivered and not even found in spam.

So obviously with gmail being so immensely popular, i reconfigured mercury to use its SMTP relay client instead and send mail through plusnet - relay.plus.net. Great.. Yahoo now accepts and delivers email... but now Gmail doesn't. Emails bounce back harping on about a missing message-id in the headers.. even though it's definitely there (they helpfully include the sent email as an attachment.. and when viewing it, it most definitely shows the message-id).

I've created an SPF record.. 

Help!

I'm not normally troubled with this kind of thing, I've setup DNS, created my own DNS server (and DHCP server) and this isn't the first website i've run either but i'm completely stumped on this.

[#2]

In a couple of cases I've had to set up transport mappings to route outgoing e-mail via specific relay clients based on the destination address. I'm using Postfix, and it is straightforward with that - but I expect other mail systems can do the same thing.

[#3]

I had a bunch that might be a workaround someone might suggest.

I suspect I'll have to use phpmailer and use different SMTP accounts based on destination domains..

[#4]

@7up 

This is odd and a tad worrying.  Is all of the following correct...

• You are sending from your own domain name
• The outbound server is set to relay.plus.net
• Your domain name management (DNS) is not with Plusnet
• Your domain has a valid SPF record (not too deep)
• Only Gmail is rejecting delivery

Have you checked the SPF validity using something like MX Lookup Tool - Check your DNS MX Records online - MxToolbox?

Do you have the detail of Gmail's rejection?

Is the connection to the SMTP server authenticated?  If you are connecting over a Plusnet network, unauthenticated access to the SMTP server is permissible, but that might cause Gmail to belly ache, because that is what Gmail does!

[#5]

Well i finally got to the bottom of it..

I had used relay.plus.net in the spf record. Turns out i needed to use avasout-peh-002.plus.net

Changed that and emails now get delivered with no problems it seems!

Gmail and yahoo now pass it and deliver it (the email headers confirm that the emails pass their SPF check) and I've got an email out to a msn user which hasn't bounced yet.. looks promising!

It was another topic on this forum that made me think about the wrong domain being used in the spf..

Thanks for your thoughts guys!

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