Forum Discussion

Brian_Brehart's avatar
Brian_Brehart
Icon for Altostratus rankAltostratus
Feb 18, 2020

Compression stripped by Silverline

We've recently experienced slowdowns serving web pages, and here's something we've found: Apparently, when traffic passes through the WAF, the WAF strips out the following line: Content-Encoding: gz...
compression
F5 Cloud Services
gzip
security
Silverline
Aaronb's avatar
Aaronb
Icon for Employee rankEmployee
Mar 12, 2020

F5 Silverline inserts a Via header in all HTTP requests sent to back-end web servers.

  • However, some web servers do not compress data if a request contains a "Via" header.
  • This can lead to longer load times for clients as well as increased bandwidth usage.

Please consult your server documentation for details. 

IIS server:

https://docs.microsoft.com/en-us/iis/troubleshoot/performance-issues/troubleshooting-iis-compression-issues-in-iis6-iis7x

appcmd set config -section:system.webServer/httpCompression /noCompressionForHttp10:"False" /noCompressionForProxies:"False" /commit:apphost

NGINX

https://nginx.org/en/docs/http/ngx_http_gzip_module.html#gzip_proxied

Syntax: gzip_proxied off | expired | no-cache | no-store | private | no_last_modified | no_etag |auth | any ...;

Default:

gzip_proxied off;

Context: http, server, location