Cisco VPN Client and MS Proxy 2

I cannot make a Cisco VPN Client connection through an MS Proxy 2 on an XP machine. I can use a separate Dial-up connection and use the VPN fine. Is there a way to make IPsec connections through an MS Proxy 2 using a Cisco VPN Client? If so, what do I have to do to the MS Proxy 2 to allow a VPN conection?
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moduloConnect With a Mentor Commented:
Finalized as proposed


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Are you dialing into the MS Proxy machine or dialing Out from that proxy?  

Why are you using the Cisco VPN client?

When you say you can use a separate dial up connection and get it to work you mean this problematic connection is a broadband connection?

More info please.  :)
mflowersAuthor Commented:
We have a Cisco VPN 3000 Concentrator with VPN Client Release 3.5 and one of our subs has an internet connection with a Microsoft proxy 2. I believe it is DSL. They also have another connection they can use via dial-up which works with the Cisco VPN client (3.6.2). They are trying to connect to us but their MS Proxy 2 doesn't allow the return packets, as it gives this error: "VPNStart callback failed "CM_IKE_ESTABLISH_FAIL".
I found this disturbing bit of info on the Cisco site

> Note: IPSec over TCP does not work with proxy-based firewalls.

I guess it may not be possible. As they say, "you can't get there from here."
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nouelletteCommented: may be right, it might NOT be possible. thing I always do, if I have the extra time to test open ALL connections...or creaet a filter on Proxy that allows ALL communication in and out.  I then test my troublesome connection this way.  If it works...I know then it's just a matter of locking down ports one at a time or deducing that way.

I'm wondering if they reconfigure proxy to allow all communications in...if that VPN connection would work or not?
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mflowersAuthor Commented:
Ok. Clean it away. We ended up not using the Cisco client since it was causing us so much grief. According to Cisco, it isn't able to go through an MS Proxy 2, and our networking guys came up with an HTTPS that is just as secure (as far as the corporate guys know). Thanks for the replies.
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