Hello,

I am being blocked by Yahoo with the error message: 451.4.4.0 Primary IP address responded with "421 4.7.1 [TS03] All message from x.x.x.x will be permanently deferred; Retrying will NOT succeed. See http://postmaster blah blah blah.

I found that this is a problem with the DKIM and I used https://github.com/Pro/dkim-exchange open source to try and remedy this but I was unsuccessful. I don't think I am doing anything wrong as I followed the instructions to the letter. 

These are the results of the auth-results@verifier.port25.com email.

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Summary of Results

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SPF check:          pass

DomainKeys check:   neutral

DKIM check:         neutral

Sender-ID check:    pass

SpamAssassin check: ham

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Don't know what other info to give...

Please help...

Hi

This could be an issue with incorrect entries in a hosts file or possibly an issue with firewall blocking queries for specific domains.

1. Check for hosts file on the mail server and see if it has entries in it for these domains.

2. Also check from another internal client pointing to the INTERNAL DNS server and use NS lookup to try to resolve the MX records for the domains in question. 

3. If step 2 fails, Point the same client to an external DNS server (4.2.2.2 for example) and do the same test.

Cheers

From your auth-result, you don't have DKIM and DomainKeys signed.

Here are some tips, hope it could be helpful to you.

It looks like that your IP address is blocked by Yahoo, so i suggest that you set DKIM and Domainkey correctly at first, then check your email server or email content based on the following rules.

then you can fill this form:

Yahoo Bulk Sender Contact Form

To increase the inbox delivery rate of your messages, make sure that all recipients on your distribution lists actually want to receive the mail. Have a look the following sections for some tips on how to make sure your messages are welcomed by most email providers.

Common Rules

• Send email only to those that want it.
• Never hide your IP and real email address.
• Never use dynamic IP address to send email directly.
• Never use a public proxy server to send email.

Authentication and Identification

DKIM/DomainKeys - signning your email with DKIM/DomainKeys.

Set up DKIM in Exchange Server 2007/2010/2013
Set up DKIM in Exchange Server 2003
Set up DKIM in IIS SMTP Service


SPF Record - publishing an SPF record.
SPF Record Project
Sender ID Framework SPF Record Wizard

PTR Record

Keep valid reverse DNS records for the IP address(es).
PTR record, or pointer record, enables someone to perform a reverse DNS lookup. This allows them to determine your domain name based on your IP address. Because generic domain names without a PTR are often associated with spammers, incoming mail servers identify email from hosts without PTR records as spam.

You should ask your IP address(es) provider (not domain provider) to set a PTR record for your IP address(es) and I suggest that you use your domain name as the record value.

SPF,DomainKeys and DKIM Test Tool

Subscription and Unsubscribing

Each user on your distribution list should opt to receive messages from you through an email asking to subscribe to your list or manually checking a box on a web form, or within a piece of software.
A user must be able to unsubscribe from your mailing list through a link or replying to your email with an unsubscribe request
Body Format

• Link to domains, not IP addresses in email html body.
• Do not include JavaScript in email html body.
• Do not include embedded Object (ActiveX/Flash) in email html body.
• Don't include HTML forms in email html body.

Realtime Black List

Check if your IP address(es) or linked domain(s) in email body is in realtime black list by the following online tools:

http://www.anti-abuse.org/multi-rbl-check/
http://mxtoolbox.com/blacklists.aspx

Yahoo Bulk Email Sender Guidelines

Yahoo Email Sender Guidelines

If you are sending mail in accordance with above guidelines and still have problems to deliver email to those email providers, you can contact the support by the following URL:

Yahoo Bulk Sender Contact Form