Version:            (using KDE KDE 3.3.0)
Installed from:    Debian testing/unstable Packages
OS:                Linux

When opening a website in konqueror the DNS is queried many times for the same address. E.g. for kde.org ngrep shows 9 queries to resolve "kde.org". Clearly, only the first is necessary. For "kde-look.org" it results in about 20 queries (plus queries for 2 other hosts). It is much worse for heavier sites that I tried - especially with many images it seems a lookup is done for each and every image. 
Replies to other similar bug reports suggest that glibc and its name resolving is not correctly installed. To my best knowledge I have checked all configuration files like /etc/resolv.conf and /etc/host.conf etc. and found no wrong configuration. I also tested some sites with Firefox. It only did exactly one DNS query per host and then seemingly used (glibc's or its own?!) resolver cache which I would regard clever behaviour. 
I also wanted to test the performance difference (the penalty for doing 8 unnecessary lookups is supposed to be quite high on slow connections (think of 56k modems or especially GSM modems in mobile phones with 9600bps which I have to use from time to time)). So I entered some hostnames for testing into /etc/hosts. This would make zero lookups and I wanted to see if there is some noticable difference then - but /etc/hosts is simply ignored by konqueror so I can't tell you hard numbers (for this I'm now going to file its own bug report)... but I really think this issue would gain some visible rendering performance.