By taking a closer look at the log-files I found a lot error entries with the following message:

AH00717: Premature end of cache headers.

I tried to google but I couldn’t find anything about what causes these problems. I’m not even sure which headers are meant in this context, cache entry header or request header?


I’m pretty sure this errors caused the problem mentioned in my previous post. Although the AH00717 occurred at least for the last three month every day. But only for one specific site, not all the sites the cache is responsible for.


Von: Alexander Härtig []
Gesendet: Freitag, 18. Dezember 2015 18:28
Betreff: [users@httpd] mod_cache/mod_cache_disk responses missing Content-Type header




for our customer we set up several Apache httpds (Server version: Apache/2.4.16 (Amazon)) in Amazon Web Services EC2 instances across the world. These httpds act mainly as caching proxies that are connected to a central web application. For caching we use mod_cache_disk.

A couple of days ago one instance served responses with missing Content-Type and Content-Encoding header, resulting in download dialogs popping up when customer tried to open the page, as the content was interpreted as application/octet-stream. The downloaded data was the expected response: a gzip-compressed html-file. We could tell that the data was served from the cache as we add a custom response header that states if there was a cache-hit or not. So we took a look at the relevant *.header-file of the cache entry of the page but it didn’t have any abnormalities.

After clearing the cache manually everything went back to normal.


Does this behavior sound familiar to anybody?






Alexander Härtig

software engineer


dmc 030 GmbH

Kohlfurter Strasse 41/43

10999 Berlin (Germany)

Telefon: +49 30 308 3393 - 70

Telefax: +49 30 308 3393 - 93




Handelsregister: AG Berlin Charlottenburg HRB 129396 B

Geschäftsführer: Daniel Elsässer, Andreas Magg


// the diconium companies:

dmc commerce consultants | dmc digital media center | dmc 030 | ro11 | embitel | CINTEO


stuttgart // berlin // karlsruhe // bangalore // detroit



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