Comment 23 for bug 113201

Finally I've tracked down the same problem on my Linux box here. I'm using
Mozilla, Galeon and Epiphany, all suffer the same long delay. IT is quite good
demonstratable on EBay when loading large list of offered articles.

As soon as I remove the isInNet() call from the PAC everything works fine again.
With that call the UI most times (! but not always) freezes for up to nearly 1
minute.

As described below, this seems to come from a synchronous DNS lookup. I can't
understand why waiting for a new page to come blocks the whole UI? At least
since tabbed browsing is available, I thought every page is loaded and displayed
by a seperate thread. And this should eliminate this problem. Even if DNS lookup
is synchronous.

Even if "using isInNet()" is not good practice and the warning for an DNS lookup
for every URL is in the documentation, "isInNet()" is a very handy function and
should not be removed or discouraged. For _every_ URL and every img tag a DNS
lookup is necessary (probably by the Proxy-Server). So it is no problem to do a
DNS lookup by the browser too. BTW: are the results from isInNet() cached somewhere?

The problem is here for Kernel 2.4 and 2.6. (BTW: I've enabled IPv6). I've
installed the mozilla-browser 1.6-5 Debian package (and others).