Troubleshoot 550, 553, and relay-prohibited errors

Relaying occurs when an e-mail message is sent to an e-mail address whose domain (the name after the @ symbol, such as is not processed by the Simple Mail Transfer Protocol (SMTP) or outgoing server that the sender is requesting to deliver the message. The SMTP server must connect to another SMTP server to relay the message. When you send an e-mail message that encounters a relay error, your SMTP (outgoing) e-mail server might return your e-mail message with an error message such as one of the following:

Have you been Blacklisted?

It may pay to check that your email has not been black listed. This is easy to identify and fix.
Check that your modem IP Address has not been black listed.

Visit this website to find out what your IP Address is:

Then check if the IP address has been black listed by visiting this site and the blacklists Enter your IP Address (from the supportdetails website), if you have a block you can fill in the simple form on the website to remove the block on your IP Address.

Telecom Broadband - Port 25 Unblock

What is Port 25?

In an average week, Telecom's anti-spam filter detects, marks up or removes over 40 million bits of spam email.

That's a very good start however, as you probably know, some spam still gets through. To help tackle this problem, we're filtering email traffic on the email Port 25.

Port 25 is the dedicated Internet port used for sending email. It is also used by spammers to send unwanted email, new viruses and, worms will often spread across the Internet using this port. That's why we filter it.
Filtering Port 25 started on 26 April 2006.

Do other Internet providers filter port 25?
Filtering port 25 traffic is now regarded as international best practice to help prevent the spread of spam, worms and viruses. Many large ISP's in Europe, USA and Australia have now adopted this practice.

Will this stop me sending or receiving my Telecom emails as usual?
It will probably only affect you if you send or receive emails using your own mail servers. The majority of customers will not be impacted. If you are using your own email servers then you should consider opting out below or changing your email to use the Telecom mail servers.

I also use email from a different provider on the Internet. Will I still be able to send and receive my email via that provider?
If you use non-Telecom email accounts filtering, Port 25 should not prevent you using them.

Will it prevent me from sending or receiving emails using web based email providers such as and
No. Online email such as Yahoo! and Hotmail are all web based services and allow you to use your web browser to access them. Your web browser uses a different port from your dedicated email program and we will not be filtering that port.

Will this stop someone sending me an email?
No. You would only have trouble receiving email if you are not using the Telecom email servers. If you are you using your own email servers then you should consider opting out below or changing your email to use the Telecom mail servers.

Are there any security risks associated with opening port 25?
When you receive an e-mail on port 25, your network generally assumes that the transmission is "e-mail" and allows it to flow through to the e-mail server. The transmission may be a valid "e-mail", but it could be a virus or a spam, or something much worse. Regardless of the true intent of the e-mail, at this point it is now upon your system, network and security to guard against these threats.

What can I do to help prevent the spread of spam and virus?
We recommend that you always use a security suite consisting of Anti-Virus, a Firewall and anti-spyware (such asĂ‚ Telecom Security Suite ). Plus, it's important to keep your operating system up to date.
We also advise not to open suspicious attachments or links in emails.

Opting out of port 25 filtering

If you wish to apply to opt out of Port 25 Filtering please visit: PORT 25 OPTING

After successfully opting out, you will need to restart your broadband modem. To do this, remove the power cable from the back of the modem and wait until all the lights are out then replace the cable. You'll need to wait until the lights on your modem come back on before trying your Internet connection again.

To opt back in at any time simply follow this same link. Remember you'll need to re-boot you're your modem for the change to take effect.

If you have any questions about port 25 filtering please emailĂ‚ This email address is being protected from spambots. You need JavaScript enabled to view it.This email address is being protected from spambots. You need JavaScript enabled to view it.

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