New Pro 2040 Sonicwall - I need to get to a public address from within the network

Posted on 2009-07-07
Last Modified: 2012-05-07
I have just installed a new Sonicwall Pro 2040 firewall.  I have a server that I need to get to from the outside.   I created a one to one NAT and that works 100% fine when access from outside the network.  
However, when I try to access the server from INSIDE the network, I am unable.  Any ideas?

Here is the setup: - public
host2 - private
one to one NAT from to

If I ping from inside the 10.1.1.x network, I get a request timed out.
If I ping from the internet, I get successful pings.
If I ping from our MPLS office, I get successful pings.

I had an old Pro 200 Sonicwall with this exact same setup and I was able to ping from within the network.

Question by:scottvin
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LVL 32

Accepted Solution

dpk_wal earned 500 total points
ID: 24801996
Usually with most hardware firewall ingress and egress interface for a packet cannot be same; also called event horizon problem; as a result you are facing the problem.
Very few vendors like cisco have solution for this problem by implementing something called hairpin.

Well there is no setting on the Sonicwall firewall which would solve this issue; but there are workarounds.

1. Configure the internal DNS caching server for two zones, which would resolve to internal IP for local clients and to public IP for others.

2. You can edit the hosts file on each machine and configure local IP there, so all the packets would go to the internal server.

3. Use internal IP instead.

Thank you.

Author Comment

ID: 24803408
I see.. So the early Sonicwalls allowed this type of behavior and the new ones don't?
LVL 32

Expert Comment

ID: 24803687
I am not too sure why it worked on older firewall in the first place. May be there was some internal DNS entry earlier which might have been modified/deleted.

Can you update if there is any change which was done on the network, other than replacing the firewall.

Thank you.
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Author Comment

ID: 24803712
Yes, we changed over to a new ISP as well but I am sure it is the new firewall.  The old one was over 6 years old.

We are going with option #2 by the way.  It's only a handful of machines but I wanted to see if it's possible.


Author Closing Comment

ID: 31600698
Nice, quick, concise answer!
LVL 32

Expert Comment

ID: 24809986
Thank you.

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