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Raj_Barre's avatar
Raj_Barre
Icon for Altostratus rankAltostratus
Sep 08, 2018

Download issues with low speed connections on ASM

I am facing a peculiar problem with downloads for one of the applications. Download of large files are failing through ASM. For example, when I try to download a 400Mb file, the download reaches around 80 Mb and abruptly closes itself.

 

During the download, I could see the below error in the application security logs. ASM filtered HTML exceeded limit: event code C180 Filtered Response HTML exceeded max limit

 

Our assumption is that due to slow speed, buffers are being accumulated at the WAF. Tried changing the Response HTML limit to 104Mb (maximum limit) but that did not resolve the issue.

 

Any guidance is much appreciated.

 

ASM Advanced WAF
security

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  • samstep's avatar
    samstep
    Icon for Cirrocumulus rankCirrocumulus
    Sep 16, 2018

    This has nothing to do with slow speeds. ASM is not designed to inspect files bigger than 50Mb.

     

    You can increase this limit by changing the max_filtered_html_length setting. - check the support article here:

     

    https://support.f5.com/csp/article/K10007

     

    As these are downloads from your own website I assume these are trusted files, so technically speaking you don't need to process them with ASM. In such case another option is to simply configure ASM to ignore these large file extensions (e.g. .ZIP extension) or disable ASM using an iRule - you will find many examples here on DevCentral