OS: XP Pro SP3
Email client: Outlook 2003, served by Exchange 2007
VPN: SonicWall GVPN 4.2.6
I have a user (an executive within the company, of course) who sometimes connects via VPN to send emails (see software above). We recently added an image to the signature in all outgoing emails - it is a 23KB image locally held on each computer.
My user finds that when he includes this image, it takes a very long time (1+ minutes is common) to send the simplest of emails - even a test with no other content. Outlook will tell us that it is trying to communicate with Exchange.... In contrast, he can send a long winded email with a 2MB attachment with no delay if the image is not included.
Both the email server and this image business are new additions, but no other users are experiencing issues.
Disabling firewall and A/V (for testing purposes only) make no difference.
This doesn't appear to be an issue when working inside the office - so I'm leaning towards the VPN client as the culprit, but everything is configured the same as everyone else and logs do not indicate a problem. VPN connection is stable and I'm able to remote into his computer and see the issue happening...