It is interesting to examine the HTTP headers of requests and
responses flowing through the caches. To get this information, I
temporarily modified Squid to write a short binary record that
indicates which headers are present. I also tracked the
The headers log file does not include URLs, so I cannot eliminate the popularity effects. There is one entry for each request from and each response to a client, so this data is from the client’s point of view.
lists the request headers and
their frequency of occurrence. It’s important to keep in mind
that most of these requests come from child caches, not from
web browsers. Furthermore, most of the child caches are also
running Squid. Evidence of this is seen in the occurrence of
headers. Both of these are added by proxies, and the latter
is an extension header used by Squid. According to this
data, around 99% of all requests come from child caches.
Table A-2. Client Request Headers (IRCache Data)
|Header||% Occurrence||Header||% Occurrence|