SonicWALL slows iTunes downloads, Software Update and Gmail attachments
I spent the last two weeks working on this with SonicWALL support, so I thought I would post the solution.
Our office found that our SonicWALL Pro 2040 began interfering with secure downloads within apps somewhere in late July 2010. Things like Gmail attachments (over https), iTunes purchases and downloads, Apple Software Update downloads, and other in-app updates and downloads. These would load up ~1MB at full internet speed, then slow to a trickle or virtually stop. Maybe a few minutes later, the download would resume.
If I disabled the SonicWALL's security services, (Gateway Antivirus, Intrusion Prevention, Anti-Spyware), the problem would go away. We went as far as upgrading our Pro 2040 to the latest NS 2400, and it too came with the same issue the moment we turned on the security services.
The fix was not available in the Pro 2040's Enhanced (4.2.1.0-20e) firmware. But the NS 2400 with the latest Enhanced firmware (5.5.2.1-5o) has a hidden setting which can be ticked and it solved our problem. Login to the SonicWALL admin page, then change ending portion of the URL from /main.html to /diag.html. Click Internal Settings > Scroll down to Security Services Settings > the tick the Enable enforcement of a limit on maximum allowed advertised TCP window with any DPI-based service enabled.
That's it. Hope this helps someone.
Our office found that our SonicWALL Pro 2040 began interfering with secure downloads within apps somewhere in late July 2010. Things like Gmail attachments (over https), iTunes purchases and downloads, Apple Software Update downloads, and other in-app updates and downloads. These would load up ~1MB at full internet speed, then slow to a trickle or virtually stop. Maybe a few minutes later, the download would resume.
If I disabled the SonicWALL's security services, (Gateway Antivirus, Intrusion Prevention, Anti-Spyware), the problem would go away. We went as far as upgrading our Pro 2040 to the latest NS 2400, and it too came with the same issue the moment we turned on the security services.
The fix was not available in the Pro 2040's Enhanced (4.2.1.0-20e) firmware. But the NS 2400 with the latest Enhanced firmware (5.5.2.1-5o) has a hidden setting which can be ticked and it solved our problem. Login to the SonicWALL admin page, then change ending portion of the URL from /main.html to /diag.html. Click Internal Settings > Scroll down to Security Services Settings > the tick the Enable enforcement of a limit on maximum allowed advertised TCP window with any DPI-based service enabled.
That's it. Hope this helps someone.
Mac Pro 2008, Mac OS X (10.6.4), SonicWALL vs. iTunes and Software Update