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What Ports Are Used by ISA04 VPN? - 12.Aug.2005 12:47:00 PM

elroyjetson

Posts: 18
Joined: 20.Mar.2003
From: Lansing
Status: offline

I have my home network protected by ISA04. I set up a VPN On my ISA box and I want to be able to access my network from work.

When I attempt to connect, my ISA box asks for credentials but cannot complete the connection.

My theory at this point is that my work Pix is not allowing traffic through because the ports ISA04 VPN needs open are closed.

What ports does ISA VPN use?

Thanks for any assistance or troubleshooting ideas.

Post #: 1

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RE: What Ports Are Used by ISA04 VPN? - 12.Aug.2005 2:49:00 PM

ClintD

Posts: 1848
Joined: 26.Jan.2001
From: Keller, TX
Status: offline

If you are getting an authentication prompt, thenthe PIX is fine.

If you're using L2TP with IPSec, then UDP 500 is needed for IKE Negotiations and while Protocol 50 for Encapsulating Security Payload and/or Protocol 51 for Authentication Header is needed. User credentials are sent over the later protocols as data. If NAT is involved anywhere, then UDP 4500 is used for L2TP with IPSec.

For PPTP, the control channel is over TCP 1723 and user credentials are sent over Protocol 47 Generic Routing Encapsulation. If you are getting a challenge for credentials, this this means that the ISA Server is receving your credentials and rejecting them - it could not reject the credentials if it did not receive them.

What authentication method are you using on the ISA Server? RADIUS or regular Windows authentication?

[ August 12, 2005, 02:53 PM: Message edited by: ClintD ]

(in reply to elroyjetson)

Post #: 2

RE: What Ports Are Used by ISA04 VPN? - 14.Aug.2005 7:37:00 PM