Question : Can't send emails (Vista Business, United Kingdom, Demon Mailbox/Demon Broadband)

I had a call from someone who'd had their pc rebuilt by pcworld.  Everything seems to work, except they are unable to send emails.  Usual kind of problem, I will get that sorted in no time... or so I thought!

They have a Demon broadband connection, they have a Demon mail account.  Demon say they do not block any ports (e.g., Port 25 SMTP).  Tried various things with Demon on the phone:-

No Authentication, Authenticating using the broadband password, etc etc.  No joy.  I swapped from using Windows Mail to Thunderbird still no joy.  I tried using the Port 587 Submission port instead (which an official Demon FAQ suggests) and logging in to send using full Authentication.

I used www.grc.com Shields Up utility which revealed that Port 25 was Stealthed (and so too was 587).  Aha, Firewall issue.  No Firewall rules setup in Netgear 1000 router (which had recently superceded a Netgear DG834, for some unconvincing reason).  The only thing that looks like it can affect this on the pc itself is Avast, so I uninstalled that, no joy.  Turned off Windows Firewall (getting desperate now), still no joy.

I setup Outgoing Rules in the Netgear to Allow all traffic on Ports 25 and 587 - which they were already, but I set Logging to Always.  Now doing a GRC Shields Up I would expect a test of Ports 25 and 587 to show activity in the Netgear logs.  

Nothing.

I am out of ideas... Help Please!

Answer : Can't send emails (Vista Business, United Kingdom, Demon Mailbox/Demon Broadband)

that is usually a good sign your DNS is setup wrong.

make sure your dns points to your active directory server and then use the netdiag tools from Microsoft on the server to make sure your DNS is configured correctly.

you can also check the new user to see if ROAMING profile is turned on,  this could cause it slow down.