Re: no-cache request, potential denial-of-service

From: Duane Wessels <wessels@dont-contact.us>
Date: Tue, 29 Sep 1998 17:46:38 -0600

Duane Wessels writes:

>Something sort of interestin happened to one of my caches over
>the weekend. the filedescriptor usage went way up and stayed up
>around 500-600. Normally it is under 200.
>
>I found about 200 simultaneous requests coming from a cache
>in Russia. The URL was for a MSIE browser executable, about 1.8 MB.
>
>Basically every client-side request had an associated server-side
>request fetching the object. My cache was making 200 simultaneous
>requests for the same URL. Apparently, all these requests had Pragma:
>no-cache. there certainly shouldn't have been so many outbound
>requests.

BTW, I sort of left something out of this nice story.

The reason so many clients could accumulate is because the clients
were reading so SLOWLY. Anywhere from 15 to 650 bytes per second.

Duane W.
Received on Tue Jul 29 2003 - 13:15:54 MDT

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