[Bug 113201]

[Bugz-e]

We had users complain about UI hang when they typed in a non-existant
domain.  We had 30 IsInNet statements in the PAC file they were using.
Firing up Wireshark showed 2 types of lookup were attempted - normal DNS
lookup, and a netbios lookup.  Regular DNS lookups returned pretty
instantly with NXDOMAIN.

I saw the netbios lookup packets conformed to NameSrvQueryCount and
NameSrvQueryTimeout defaults as mentioned here
http://support.microsoft.com/kb/314053.  1.5seconds * 3 attempts = 4.5
seconds per IsInNet clause.

Completely turning netbios off fixed the issue, but that's clearly a no-
go (not a Windows engineer, I'd have happily turned it off!).

Someone in our team came up with the idea of cutting down on the amount
of resolving needed.

We went from the following:

=== from ===
if (isInNet(host, "172.31.0.0", "255.255.0.0") ||
    isInNet(host, "10.0.1.0", "255.255.255.0"))
    {
    return "proxy1.domain.co.uk:1234"
    }
    if (isInNet(host, "192.168.0.0", "255.255.0.0") ||
        isInNet(host, "127.0.0.0", "255.0.0.0") ||
        isInNet(host, "172.16.0.0", "255.255.0.0") ||
        isInNet(host, "172.19.4.0", "255.255.252.0") ||
        ....
        ....
        isInNet(host, "172.20.0.0", "255.255.0.0") ||
        isInNet(host, "172.21.0.0", "255.255.0.0") ||
        isInNet(host, "10.0.0.0", "255.0.0.0"))
    {
    return "DIRECT"
 
=== to ===  

var resolved_ip = dnsResolve(host);


if (isInNet(resolved_ip, "172.31.0.0", "255.255.0.0") ||
    isInNet(resolved_ip, "10.0.1.0", "255.255.255.0"))
    {
    return "proxy1.domain.co.uk:1234"
    }
    if (isInNet(resolved_ip, "192.168.0.0", "255.255.0.0") ||
        isInNet(resolved_ip, "127.0.0.0", "255.0.0.0") ||
        isInNet(resolved_ip, "172.16.0.0", "255.255.0.0") ||
        isInNet(resolved_ip, "172.19.4.0", "255.255.252.0") ||
        ....
        ....
        isInNet(resolved_ip, "172.20.0.0", "255.255.0.0") ||
        isInNet(resolved_ip, "172.21.0.0", "255.255.0.0") ||
        isInNet(resolved_ip, "10.0.0.0", "255.0.0.0"))
    {
    return "DIRECT"

======

It's not a fix, but it's 1001 times better than what we had before, hope
this helps someone with a similar situation.

-- 
You received this bug notification because you are a member of Mozilla
Bugs, which is subscribed to Mozilla Firefox.
https://bugs.launchpad.net/bugs/113201

Title:
  firefox spends lots of time hung

To manage notifications about this bug go to:
https://bugs.launchpad.net/firefox/+bug/113201/+subscriptions