Undelivered Mail Returned to Sender?


New Email
Hi folks,

Hoping I can get some assistance with a period problem my father is having. His email provider is Cox.net. For awhile, he was continuously getting the following email in his inbox:

From: MAILER-DAEMON@mail2world.com (Mail Delivery System)
Date: July 2, 2013, 4:21:59 PM EDT
To: dasmith1@cox.net
Subject: Undelivered Mail Returned to Sender

This is the mail system at host c2mailgw11.amadis.com.

I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can
delete your own text from the attached returned message.

                  The mail system

<murc34o@excite.es>: host m2w-in1.ctmail.com[] said: 550 5.1.1
   <murc34o@excite.es> is not a valid mailbox (in reply to RCPT TO command)

This type of message was arriving in his inbox on a very regular basis for awhile, originating from domains all over the world, with from what I recall no apparent pattern. They have slowed down considerably, but still show up once in awhile.

I've had him change his password, with no luck. Anybody know what this type of email indicates? Does someone have access to his account, or has his address just been collected and is being used by spammers?

Thanks so much!


Valued Member

It looks to me as if your father is the victim of a "joe job" where some spammer has sent a large number of messages using your father's address as the return address.

Undeliverable messages sent out by the spammer are then returned to your father's address automatically by the receiving SMTP servers that cannot find a local recipient to deliver the message to.

Unless your email service provider has some sort of backscatter prevention technology in place (I know FastMail.FM and maybe Tuffmail provides this), there's nothing you can do except wait for the storm to pass, which it usually does, luckily. Changing the password does nothing to help.

It also looks like you accidentally pasted your father's real email address in your message. You probably want to edit that out.