After my spam filter has been inactive for…

After my spam filter has been inactive for more than two weeks, I finally had the pleasure to investigate what went wrong during the upgrade of my system to Debian Wheezy. Back then I took the conservative approach and kept my old configs when in doubt, especially when they were personalized to my tastes. Unfortunately DSPAM wasn’t so nice as to pass Exim any meaningful error message.

Long story short, the DSPAM package changed the location of its storage drivers. Inserting „x86_64-linux-gnu“ in the StorageDriver entry in dspam.conf solved the problem. Wouldn’t this be the first thing to look for when reading „transport returned 1 from command: /usr/bin/dspam“ in the mainlog?!

Android Z-Push

For weeks I had the intention to use my Android phone with Zarafa and Z-Push. However, my phone always reported that protocol version provided by the server would not be supported. I had a day off today and dug into the code (first Z-Push, then CyanogenMod 10) to track down the problem. It seemed like there would be a problem with the OPTIONS request in ActiveSync and the headers sent by Z-Push. I ended up using Fiddler to inspect the HTTPS traffic, in particular the headers and it turned out that Z-Push did not send the headers to identify the ActiveSync protocol. But the PHP-code (already messed with debugging output of my own) did send the headers.

Surprisingly, a minimal PHP script that did nothing by sending headers also worked. After a while it seems like the PHP output buffering (ob_start) dropped the headers, but then ob_clean or _flush at before and/or after the header call didn’t change anything.

Staring at the Fiddler traffic of the working testing code brought the saving idea: I had mod_pagespeed enabled (which I noticed, because it also added a header of its own). Turning it off made everything work!

Conclusion: Z-Push is incompatible with mod_pagespeed!