We run Pound in a small web cluster for serving an online medical
learning environment for the entire medical degree program, here at
newcastle. Pound works brilliantly.
Recently we've purchased several SSL certificates (from Thawte) for the
above site and others that are hosted on the cluster. We seem to have
hit a bit of a speed-hump, however.
The situation we have is this:
A Debian/Linux front end load balancer running Pound-1.8, listening on
several interfaces, including two hosts that we have a certificate each
Requests for page content are directed to 1 of 3 backend Zope/ZEO
servers. Certain URL's are sent to a single backend server running
Apache - these are requests for static files, page images, documents,
resources - stuff that we didn't want Zope tying itself up serving (big
powerpoint docs, word files, pdfs, etc).
The problem is that since installing the certificate (installed as a
private key + certificate chain), we are now getting a weird slowdown
with IE based clients.
Connections are made to the site fine, the certificate is accepted
without error. Normal browsing of the SSL sites are fine. However, when
any static files (.doc, .pdf, .ppt etc, but not the images, which are on
every page) are served many, but not all, client machines experience a
slow down of 20 or 30 seconds until the document is opened. The slow
down is not present in non-IE browsers (Firefox, Mozilla, Opera - the
document is always opened instantly). From the logs on the Apache side
of things the files are served in almost exactly the same amount of
time, whether the connection is via non-SSL, self-signed-SSL or
However, quite strangely, if I change the certificate to a self signed
version (again, a key + cert chain), the slow-down at the client
The following commands were used to generate both the self signed
certificate, and the request for the Thawte certificate:
openssl genrsa -out $KEYNAME.pem 2048
openssl req -new -key $KEYNAME.pem -out $CERTREQ.csr
openssl req -new -x509 -key $KEYNAME.pem -out $CERTFILE.pem -days 1095
Anyone have any ideas as to why we should get a notable
hang/timeout/slowdown with IE when serving these files, and not from any
The big problem is that the campus wide browser is, of course, IE.
John Snowdon - IT Support Specialist
School of Medical Education Development
Faculty of Medical Sciences Computing
University of Newcastle
Email : j.p.snowdon(at)ncl.ac.uk