Network transparent XS services - limitations and alternatives

david at david at
Tue Aug 26 01:56:05 EDT 2008

On Tue, 26 Aug 2008, Martin Langhoff wrote:

> On Tue, Aug 26, 2008 at 3:40 PM,  <david at> wrote:
>> On Tue, 26 Aug 2008, Martin Langhoff wrote:
>>>  - Do HTTP clients using a proxy do not perform DNS lookups? My
>>> understanding is that they do not, but I am not 100% certain of
>>> whether this is specified, and how actual clients behave.
>> many clients do still do the DNS lookups.
> Have you got more info on this? Which ones do you know or suspect?

firefox has to if the proxy.pac contains javascript commands that make 
decisions based on IP, but with a trivial (IP) entry it doesn't. watch out 
for 'automatic proxy settings' popping up

I don't remember others at the moment, but I remember running into 
problems with various tools in the past (my work environment consists of 
many different networks, with proxies, but not routing between the 
networks. nowdays I just either use IP addresses or make sure that every 
system/proxy in the path can resolve the name.

David Lang

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