Airport Extreme Blocking VPN Connections

[7302473]

One of our Executives is attempting to VPN into our office via a L2TP VPN profile (which I created on my own iMac, tested, exported, and gave to him). When he attempts to connect to our office via his iMac (or MacBook) at home, he receives a prompt for his username and password, the VPN states "Connecting.." for about 1 minute, but before it is able to successfully connect it eventually times out and the connection fails to establish.

I personally believe that the root cause of this issue is his Apple Airport Extreme Base Station he has at home.

I have eliminated all other devices or configuration issues because:

1. I am able to connect into the office via my iMac at home (connected to a D-Link router).
2. When he brings his MacBook into the office and I segment it outside of our LAN and attempt to VPN into our office, it works fine.
3. This issue is occurring with both his iMac and MacBook - which are both connected to his AEBS at home.
4. I have tested his credentials both on my iMac and on his MacBook (when it is in the office) and our VPN accepts his credentials. However, when he is at home, it's a completely different story.

We are running a SonicWALL Network Security Appliance in our office. I also have eliminated the chances of our IP Addresses conflicting because our office is 10.11.12.0/24 and his AEBS is 10.0.0.0/24.

Is there something I have to do or configure on his AEBS to allow his iMac and MacBook to connect to our office's VPN?

 

[NogbadTheBad]

Is he running the latest version of firmware on the AEBS ?

Have you tried putting the IP address of his device into the AEBS into the DMZ / default host ?

Not for a fix just for a quick check.

Maybe its MobileMe :-

http://support.apple.com/kb/HT3944

 

[NogbadTheBad]

Just googled free l2tp and found this :-

http://www.freeusvpn.com/free-l2tp-vpn/

I can connect fine via my Timecapsule without any changes.

macbookpro:~ AndyK$ ifconfig -a

en1: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
ether 00:25:00:49:80:5a
inet6 fe80::225:ff:fe49:805a%en1 prefixlen 64 scopeid 0x5
inet 172.16.1.51 netmask 0xffffff00 broadcast 172.16.1.255
media: autoselect
status: active

ppp0: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1280
inet 10.33.0.17 --> 10.33.0.1 netmask 0xff000000

macbookpro:~ AndyK$

The netmask looks a little odd, I guess they don't do classless, I thought everyone did these days.

 

[7302473]

So I have finally solved this issue!

Originally in the VPN configuration for Mac OS X, I had set the Server Address as "vpn.ourdomain.com" - which works fine on all devices, except those behind an AirPort Extreme. Once I put in the actual IP Address of the server, the VPN connected and authenticated properly and he was able to use RDC to access his local workstation in the office.