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VPN help:  error 721, the remote computer did not respond

Posted on 2004-10-21
Medium Priority
Last Modified: 2011-10-03
I am trying to connect using VPN to a SBS 2003.  I'v enabled port 1723 for VPN. I got the about error message. I'c been searching for solutions and haven't found one.  Help me please!!!!

Client : window xp
Host: SBS 2003 with SonicWall router
Question by:lutt
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Expert Comment

ID: 12380705
Enabled port 1723 on what?  I'm assuming a router/firewall of somekind.  Does it allow ipsec passthru.  You also need to enable GRE 47.  On some routers this is IP protocol 47.  NOT PORT 47.

What equipment are you using for the VPN? I assume all details are setup correctly in the VPN connection.  Correct Target IP etc.?


Author Comment

ID: 12383582
port 1723 and ipsec are enabled.  I didn't find GRE 47 or IP protocol 47. Can you give me some detail on how to enable it?


Expert Comment

ID: 12398189
Sorry no can't tell you how to enable, not all routers have it, and I don't know what equipment you are using.  Does your Router have a VPN passthru option?  What is the equipment you are using?  If your router has a VPN passthru option that will enable the necessary ports and protocols.

Difficult to say without fully knowing your setup.
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Author Comment

ID: 12401609
my router is sonicWall TZ170(Sonic OS Standard 2.2)

Expert Comment

ID: 12401765
Well according to the specs of that device, it supports VPN passthru.  Have you found the option to enable this?

Unfortunately I don't know the sonicwalls interface so I can't help you, but if it supports it there should be an option somewhere to enable Passthru.

Once that is enabled, then assuming the VPN client is correct it should work.

Not sure if this will help but it is a pdf detailing the setting up of VPN using sonic products.


Basically I'm assuming that everything is fine on the client end, and the VPN host end.  In which case there is something blocking VPN packets.

Find that and you are sorted.

Unfortunately I don't know your gear well enough to point you in the right direction, sorry.  

Accepted Solution

SKULLS_Hawk earned 1400 total points
ID: 12401821
Is 2003 sbs the VPN endpoint?  Is that the device that authenticates?  Is that setup correctly ?  Possibly the router is configured correctly but there is a problem in another area?

Expert Comment

ID: 14343304
It is not necessary to add GRE (IP protocol 47) to the SonicWALL in order to support PPTP pass-through (either for a client connecting to a server on the Internet, or clients on the WAN connecting to a server on the LAN side). GRE is handled automatically as needed whenever a PPTP connection is established.

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