10.7 VPN Config with Server.app Not Working

• I have a clean install of 10.7.2 running on an Xserve.
• Configure VPN using the new method through the Server.app, no problems.
• Generate .mobileconfig file and install on remote systems
• all necessary ports have been opened on Firewall for server and for external clients (note that the problem exists even with firewalls disabled)
• attempt to VPN into server and receive error message: "The L2TP-VPN server did not respond. Try reconnecting. If the problem continues, verify your settings and contact your Administrator."
• I have verified that the user account has VPN enabled; correct SharedSecret, etc.; even with admin account this fails

Any thoughts or wisdom would be greatly appreciated.

Resulting log is:

10/18/11 2:26:45.416 PM configd: SCNC: start, triggered by System Preferen, type L2TP, status 0

10/18/11 2:26:46.971 PM pppd: pppd 2.4.2 (Apple version 560.13) started by justinhendrix, uid 501

10/18/11 2:26:47.419 PM Firewall: Stealth Mode connection attempt to UDP 172.20.20.236:63220 from 198.6.1.122:53

10/18/11 2:26:50.630 PM pppd: L2TP connecting to server 'c-71-201-174-210.hsd1.il.comcast.net' (71.201.174.210)...

10/18/11 2:26:50.633 PM pppd: IPSec connection started

10/18/11 2:26:50.645 PM racoon: Connecting.

10/18/11 2:26:50.645 PM racoon: IPSec Phase1 started (Initiated by me).

10/18/11 2:26:50.646 PM racoon: IKE Packet: transmit success. (Initiator, Main-Mode message 1).

10/18/11 2:26:50.792 PM racoon: IKE Packet: receive success. (Initiator, Main-Mode message 2).

10/18/11 2:26:50.796 PM racoon: IKE Packet: transmit success. (Initiator, Main-Mode message 3).

10/18/11 2:26:50.873 PM racoon: IKE Packet: receive success. (Initiator, Main-Mode message 4).

10/18/11 2:26:50.886 PM racoon: IKE Packet: transmit success. (Initiator, Main-Mode message 5).

10/18/11 2:26:51.051 PM racoon: IKEv1 Phase1 AUTH: success. (Initiator, Main-Mode Message 6).

10/18/11 2:26:51.051 PM racoon: IKE Packet: receive success. (Initiator, Main-Mode message 6).

10/18/11 2:26:51.051 PM racoon: IKEv1 Phase1 Initiator: success. (Initiator, Main-Mode).

10/18/11 2:26:51.051 PM racoon: IPSec Phase1 established (Initiated by me).

10/18/11 2:26:51.052 PM racoon: IPSec Phase2 started (Initiated by me).

10/18/11 2:26:51.053 PM racoon: IKE Packet: receive success. (Information message).

10/18/11 2:26:51.055 PM racoon: IKE Packet: transmit success. (Initiator, Quick-Mode message 1).

10/18/11 2:26:51.149 PM racoon: IKE Packet: receive success. (Initiator, Quick-Mode message 2).

10/18/11 2:26:51.150 PM racoon: IKE Packet: transmit success. (Initiator, Quick-Mode message 3).

10/18/11 2:26:51.151 PM racoon: IKEv1 Phase2 Initiator: success. (Initiator, Quick-Mode).

10/18/11 2:26:51.151 PM racoon: IPSec Phase2 established (Initiated by me).

10/18/11 2:26:51.151 PM pppd: IPSec connection established

10/18/11 2:27:11.152 PM pppd: L2TP cannot connect to the server

10/18/11 2:27:11.829 PM racoon: IKE Packet: transmit success. (Information message).

10/18/11 2:27:11.829 PM racoon: IKEv1 Information-Notice: transmit success. (Delete IPSEC-SA).

10/18/11 2:27:11.830 PM racoon: IKE Packet: transmit success. (Information message).

10/18/11 2:27:11.830 PM racoon: IKEv1 Information-Notice: transmit success. (Delete ISAKMP-SA).