SMTP Relay

Level 2

I have been relaying email, using sendmail, from my home network (connected via TPG NBN) through This used to work, but as of about 2am Fed 20th this stopped working with "530 Authentication required".

It used to be that I only had to authenticate from laptops/mobile devices which were not conected through TPG broadband.

Is this a policy change or a misconfiguration?

Level 15

Hi @iandall . Can you check your router's system log to see if your router had a change to its WAN ip address. If it did, there might be something about this address that needs authentication.

Otherwise, try rebooting the router to get a new address.


Level 2


I think you are onto something because I did reboot the router shortly before I noticed the problem.

I have since restarted the WAN on the router but it is not fixed. The WAN address went from 114.30.110.x to 203.206.14.y.


Level 2

Hi @david64 

I have it working. What it took in the end was power cycling the modem (I'm on HFC) rather than the router. Of course that triggers the router to acquire a new WAN address as well, so I am not sure if it is just second time lucky on the "get a new WAB address" strategy or if it was resetting the connection between the modem and TPG which was significant.


Regardless, thanks for your help.