help proving slow/failing IMAP connection

WallIT · 05-04-2011, 10:24

Hi,

(I thought I posted this yesterday but I can't find it anywhere).

I am posting on behalf of a colleague who has Virgin cable broadband at home. He has a 20mb service and a bunch of recent speed tests show he is getting an average of 19.5mb. All good.

His home PC is Windows XP, which is wired into his Virgin supplied router/modem. He uses Outlook Express to connect via IMAP to a mailbox hosted at a 3rd party ISP (which is run by a friend of his). All this was working fine until a few weeks ago. Now Outlook downloads emails extremely slowly. It barely manages text-only emails, anything with an attachment simply fails. Outlook times out and prompts the user to either wait or cancel. Sending email is quick however.

The things I have test for, so far, are...

Outlook Express - I installed Mozilla Thunderbird and configured the account on there. Same problem. Still slow to download.

Mailbox - I thought it might be his mailbox. So configured an additional account in Outlook Express to connect to a Gmail mailbox over IMAP. This downloaded emails quickly

Profile - There are two separate user profiles on his computer (him + wife). They have separate mailboxes with the same 3rd party ISP. Both have symptoms of slow/timing out email downloads

Ports - The ISP supports IMAP (143) TLS (993) - I have tried both and the symptoms are the same. The friend at the ISP also temporarily allowed connections on port 80, but again it was slow/failing to download emails.

Anti-Virus - The computer is running AVG free (version 8), which I believe does not have any Outlook Express integration. I also disabled real-time protection to see if this was affecting downloading. Same problems.

Alternate PC - To rule out the PC, I gave the user a work laptop to take home. I configured Outlook Express with his account and tested it in the office. It was quick to download email. He took this home and plugged this into a spare port on the router and I tested it remotely. It was slow to download.

Network - From this work laptop I VPN'd back into the office and tested again. It was quick. I disconnected the VPN and it was slow again.

What else is there left to test/prove? Any help/advice greatly appreciated.

M

**Stuart** · 05-04-2011, 10:30

Sounds like either the server is at fault, or there is a fault at some point along the connection from the client to the server.

WallIT · 05-04-2011, 10:44

The friend who runs the ISP says he has over 600 customers all using it without any reported problems. This has been going on for a few weeks, so I'm sure someone else would have mentioned it.

The only other explanation appears to be some odd network issue between Virgin and this particular ISP.

As a conclusive test I am shortly going to connect the laptop to his neighbours wifi to prove the problem to be network related.

I'll try to keep you posted.