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Author Topic: mx1.dynu.com does not seem to honor status 450

Jeremy Guarini

Joined: 2/27/2017

Post mx1.dynu.com does not seem to honor status 450
Wednesday, April 19, 2017 5:02:11 PM

When email is being delivered I still perform valid domain checks. The system will then return stars 450 like so

450 4.1.8 : Sender address rejected: Domain not found;

It appears that mx1 does not interpret this properly and attempts to resend the email. What is the expectation for the Email Store/Forward service when the destination does not want to accept the email?

thanks

Timothy Wilkinson

Joined: 5/3/2002

Post Re: mx1.dynu.com does not seem to honor status 450
Thursday, April 20, 2017 10:07:06 AM

You are correct about this and we will create a setting (enabled by default) to handle this. IN the meantime, you can use the Delivery Address feature to permanently stop deliveries for unavailable mailboxes.

Thank you very much for this feedback!

Rah Sharma

Joined: 11/26/2010

Post Re: mx1.dynu.com does not seem to honor status 450
Friday, April 21, 2017 1:30:48 PM

jguarini wrote:When email is being delivered I still perform valid domain checks. The system will then return stars 450 like so

450 4.1.8 : Sender address rejected: Domain not found;

It appears that mx1 does not interpret this properly and attempts to resend the email. What is the expectation for the Email Store/Forward service when the destination does not want to accept the email?

thanks


Actually, 450 is a temporary error while 550 would be the permanent error. Couple examples below:

450 Requested mail action not taken: mailbox unavailable (e.g., mailbox busy)
550 Requested action not taken: mailbox unavailable (e.g., mailbox not found, no access, or command rejected for policy reasons)

Would you be able to configure your email server to respond with 550 instead of 450?

Jeremy Guarini

Joined: 2/27/2017

rahsharma wrote:
jguarini wrote:When email is being delivered I still perform valid domain checks. The system will then return stars 450 like so

450 4.1.8 : Sender address rejected: Domain not found;

It appears that mx1 does not interpret this properly and attempts to resend the email. What is the expectation for the Email Store/Forward service when the destination does not want to accept the email?

thanks


Actually, 450 is a temporary error while 550 would be the permanent error. Couple examples below:

450 Requested mail action not taken: mailbox unavailable (e.g., mailbox busy)

550 Requested action not taken: mailbox unavailable (e.g., mailbox not found, no access, or command rejected for policy reasons)

Would you be able to configure your email server to respond with 550 instead of 450?


Let me check on changing the response code. For reference, here is a sample log entry I'm seeing

wrote:Apr 24 19:39:23 mail postfix/smtpd[9573]: NOQUEUE: reject: RCPT from mx1.dynu.com[207.38.70.35]: 450 4.1.8 <WarrantyNotice@dead.warrantycarsdirected.u>: Sender address rejected: Domain not found; from=<WarrantyNotice@dead.warrantycarsdirected.u> to=<zzzz@XXX.yyy> proto=ESMTP helo=<mx1.dynu.com>

Last edited by Jeremy Guarini on Tuesday, April 25, 2017 2:47 AM

Jeremy Guarini

Joined: 2/27/2017

Post Re: mx1.dynu.com does not seem to honor status 450
Monday, April 24, 2017 8:03:21 PM

ok, now replying with 550. Let's see how that goes.

Thanks


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