Vodafone as of late April 2010 have started blocking smtp traffic to servers that are not their own

This also covers Perlico

Taken from:

http://forum.vodafone.ie/index.php?/topic/3260-unable-to-send-email-anymore/

Vodafone rep Darren: Some changes have indeed been made: To fight spammers, Vodafone customers must use the Vodafone mail server to send mail, mail sent via other servers (other than specific corporate ones) will now be rejected. We've done this to stop our IP addresses being blacklisted by other spam prevention agencies, if spam mail is sent over our network now, we can identify the sender and take steps to address the issue.

Vodafone rep Paul:

All mails will send once either of the below outgoing servers are used.

  mail.vodafone.ie
  mail.iol.ie (for BT users.)

Open SMTP servers will no longer work for outgoing mail, one of the above 2 mail servers must be used. (Other Authenticated email servers will continue to work, such as Gmail, Yahoo mail, hosting365mail, etc.)

This is standard ISP practice, we implemented it so as to vastly reduce spam for all our customers and ensure outgoing mail doesn't become blacklisted by other mail providers.

I believe these mail settings were outlined in the welcome pack to all BT customers as well as new Vodafone at Home customers, I'll clarify this with the DSL team. Again, if you use any of our outgoing mail servers, you'll have no problems sending mails,