Imagine

Olivier Tharan olivier.tharan at gmail.com
Thu May 6 08:27:52 CEST 2010


Be careful that this check is performed for every single URL your
browser encounters, before you even know you want to hit a proxy
server or not, let alone initiate the HTTP connection. regexp and
resolver checks are quite expensive and ultimately can lead to slower
browsing for your users. This combined with broken resolvers w/ IPv6
vs. IPv4 will give you frustrated users :) "the network is slow"

I would say that the PAC file and proxy support in your browser
probably doesn't care too much about IPv6 since most URLs are
hostnames anyway and name to IP resolution is mostly done on the proxy
server (or on the local machine resolver). Of course, having a raw
IPv6 address in your URL is always interesting.

On Thu, May 6, 2010 at 1:42 AM, Matt Ryanczak <ryanczak at arin.net> wrote:
> On 5/5/10 5:48 PM, Simon Lockhart wrote:
>
> No - logic in the PAC file can be executed for every URL request (or, at
> least that was the case when I wrote PAC files about 10 years ago). I have
> no idea how much it has been updated to support IPv6.
>
>
> You are correct. I did some reading up on this and it looks like you can use
> the dnsResolve function to find the IP address for a host and then do regex
> matching to determine if it an IPv4 or IPv6 address.
>
> hostip = dnsResolve(host);
> if (shExpMatch(hostip, "/^\d+\.\d+\.\d+\.\d+$/g")) {
>     return "PROXY proxyserver:8080;
> }
> else {
>     return "DIRECT";
> }
>



-- 
olive


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