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User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.5)
Description of problem:
When using Apache as a forwarding proxy, Apache continues to download
files via http/ftp, when the client has aborted the download.
mod_cache is NOT used as caching is the job of the squid proxy in
chain with the apache.
When a user requests a huge download via http/ftp, e.g. a CD-ROM
ISO-Image and aborts this download soon after, the Apache server still
downloads the whole ISO-Image. If a user tries several time, you get
more apache-processes each downloading the whole image. This easily
leads to a DOS, because the utilization of the network connection to
the internet will go to 100% slowing down other connections (if the
line is billed by volume, it will result in higher costs, too).
You can check the running downloads e.g. with netstat.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. set up apache as forwarding proxy for http/ftp/ssl
2. start huge downloads via this proxy and abort them as soon as the
3. watch netstat for established connections and the utilization of
your outgoing network interface
Actual Results: all aborted downloads proceed
Expected Results: aborted downloads should have benn aborted by the
apache server, too
Relevant parts of the Apache configuration:
LoadModule proxy_module modules/mod_proxy.so
LoadModule proxy_ftp_module modules/mod_proxy_ftp.so
LoadModule proxy_http_module modules/mod_proxy_http.so
LoadModule proxy_connect_module modules/mod_proxy_connect.so
#LoadModule cache_module modules/mod_cache.so
AllowCONNECT 443 873
<Limit CONNECT GET POST>
Allow from 192.168.0.0/16 127.0.0.1
<LimitExcept CONNECT GET POST>
Deny from all
Thanks for the report.
Experimental test packages are now available which contain
fixes for the above issues. These packages are unsupported
and have not gone through the Red Hat QA process; feedback
from testing them out is very welcome.
Any feedback from testing these packages out is very welcome.
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on the solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.