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Can I send emails via an open relay?

Last Updated: Tuesday 27 Feb 2024

Email Support Port blocking

External Port blocking on Aussie Broadband’s network

Blocked Ports


TCP/25 (Except to our mail servers)


  • TCP/80

  • TCP/443

  • TCP/25

  • UDP/135

  • UDP/137-139

  • TCP/UDP 11211

Port 25 blocking

All residential customers have outgoing port 25 (SMTP) blocked. This will restrict customers from sending email directly to other locations on the internet. Customers will still be able to send mail via our mail server,

If you use an external mail server outside of the Aussie network, you won’t be able to send email unless you are exempt.

What do I change my mail server settings to?

If you are sending mail directly from your connection, please change the outgoing server to

If your external mail server supports ports 587 or 465, you can use these, as we aren’t blocking those ports.

Why are we doing this?

This action is being taken in response to the increasing amount of spam originating from our network. The majority of customers will not notice any change. This step is considered an industry accepted form of spam prevention and many other providers in Australia and across the world are also taking similar action against spam.

Will this affect me?

If you are using our mail servers to send emails already, you will not be affected. This is about 99% of our customers.

Business customers with static IPs will be exempt.

Incoming mail will not be affected.

But wait! I can’t change my outgoing port, and can’t use the Aussie servers

If you still require outgoing port 25 access, please contact our Support line on 1300 880 905 to discuss options.

Please note: ports can be unblocked in MyAussie®. To unblock ports, you must either have a static IP or have opted-out of CG-NAT .

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