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Level 7

Deploying proxy.pac

I'm having problems deploying my proxy.pac file.

Currently I am trying to deploy it using dhcp on my core Cisco 6513 for testing purposes.

ip dhcp pool Mcafee-pool
   network <IP>  <Subnet>
   default-router <Gateway>
   dns-server <DNS Server1> <DNS Server2>
   domain-name <Domain Suffix>
   option 252 ascii http://<Web ProxyIP>:9999/proxy.pac

Currently everything with this scope works expcept the option 252.

I do have "Automaticaly Check Settings" enabled in IE, it just never seems to get that last option.  When I run wireshark I can see all my other settings being pushed out there as well, except for that last option.

I guess I am just wondering if anyone else has any experiance deploying this using Cisco, and if so what you might have done to make this work?  Or if anyone has any other ideas on how best to deploy this?

My current network is setup with the bulk of my users on a windows active directory domain, dhcp, and using Internet Explorer.  The rest of the users are on other subnets that will route through this proxy for internet, some using firefox, and macs.  Many of these are not part of my domain and also use static IP's.

My original thoughts were to use dhcp to push out the proxy.pac, and back it up using wccp.

Any thoughts or ideas would be great!

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2 Replies
Level 15

Re: Deploying proxy.pac

One of two things is happening. Either:

You need "quotes" around the string:

option 252 ascii "http://<Web ProxyIP>:9999/proxy.pac"

Or it's not supported on the Cisco DHCP server.

I get conflicting results when I google for it, but some say it will only relay the option to another dhcp server and some say it's not supported.

Keep in mind that when you are wiresharking, the option is returned when you open the browser, not during the initial IP assignment when you boot the computer. The browser sends a DHCP Info request and the DHCP server replies with the options. Just in case you're looking at the wrong place in the packet traces.

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Level 7

Re: Deploying proxy.pac

Thanks for the response!

As for the quotes, I do have them in already, I just forgot to type them in the above posting.

Unfortunetly I think you're possibly right regarding the cisco dhcp, I've been doing google searching myself and haven't found alot regarding it....

As for the wireshark capture, you were dead on, I had been capturing packets during a an ipconfig /release and /renew.  Although even after changing it up and doing a capture while opening the IE browser, I still didn't seem to find anything happening with that dhcp option.  I  guess I'll do a little more digging.

Thanks for the response!

Message was edited by: on 4/20/10 5:04:36 PM CDT
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