Can't access seperate company LAN from our DMZ

Hi All,

I have a puzzling problem, we have:

A DMZ (10.1.8.1)
A Public Internal network (10.1.10.1)
A Private Internal network (10.1.9.1)
A sister site's network (10.1.4.1) This network is at the other end of a 100Mb LES Link

At either side of the LES link is an Avaya Layer 3 switch, (10.1.10.254) on the public internal network and (10.1.4.1) at the sister site's network.

In between the two layer 3 switches on the LES link we have a 10.1.5.1 network

Now, I have opened up rules on the FW to allow data to pass between 10.1.8.5 & 10.1.4.20

I can ping 10.1.8.5 from 10.1.4.20 and see the following tracert:

Hop 1 : 10.1.4.1 (default gateway - on Layer 3 switch at sister site)
Hop 2 : 10.1.5.2 (our side of the internal LES 100 link - on Layer 3 switch at our site)
Hop 3: 10.1.10.1 (internal public firewall interface at our site)
Hop 4 : 10.1.8.5 (destination machine on DMZ)

However, when I try to send a tracert the other way, I get

Hop 1 : 10.1.8.1 (DMZ firewall interface)
Hop 2 : 10.1.10.254 (our side of the Layer 3 switch at our site)
Hop 3 : *     *    *  Request Timed out

It IS POSSIBLE to contact the 10.1.4.0/24 site from the 10.1.9.0/24 & 10.1.10.0/24 networks, just not from the 10.1.8.0/24 networks!

I'm at the end of my tether with this now, please can someone help me!

Thanks
Andy
A4eITAsked:
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DooglaveCommented:
Do you see the ping or other traffic in your SmartView Tracker logs.  You should see encrypts going out and Decrypts coming in.

Run a TCP Dump and determine if you have ESP packets leaving your GW when you ping out.
How are they addressed, Do you have NAT enabled in any way?
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A4eITAuthor Commented:
Hi all, turns out to be a NAT problem
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