Connect two Networks together

Posted on 2007-07-19
Last Modified: 2013-12-23
I am working with two seperate networks. Both of the networks are on the seperate subnet. Here is a brief diagram.

Network 1 - subnet (running Active Directory, Exchange,DHCP,DNS,WIns servers)
Network 2 - subnet (running Active Directory, Exchange,DHCP,DNS,WIns servers)

Two networks are seperated with a Sonic 3600 Standard firewall and are connected to their seperate ISP's.
Network 1 - is connected to the T1 line
Network 2 - is connected to the ADSL
I need to join those two networks together so that I can share some files etc... im not sure what is the best approach for this.

The sonic firewalls have 3 interface ports each. 1-LAN 2-WAN 3-DMZ
Can I perhaps link the two sonic walls together through the DMZ interfaces?
Question by:Turbowy
    LVL 25

    Expert Comment

    So I take it you want to do something like this

        T-1                                ADSL
         |                                      |
       Sonic1 (DMZ)<--->(DMZ)Sonic2
         |                                      |  

    I so, then it shouldn't be a problem.  Just link the DMZ interfaces (most likely with a crossover cable) and create a small network like  and assign to Sonic1 and to Sonic2.  Then make sure to have routes in each Sonic so that it knows to find the other network thru its DMZ interface.  However, I'm not familiar with Sonicwall's so I'm not positive if its totally that simple when doing the config or not, but the logic should work provided I understood you right

    Author Comment

    Hi Cyclops3590, yes it is quite simple in sonic firewall to configure the interfaces etc... do you think that i will need to set up rules, like for example to allow traffic from DMZ > LAN and vice versa?

    LVL 25

    Accepted Solution

    Yup.  I would just make sure to put in the acls so that only the internal networks can traverse that link.  So each DMZ interface would allow any port from the other subnet to the inside subnet.  This is to prevent have someone trying to hack the network going in the ADSL line and try to go into the DMZ to the Sonic1.  (not sure why since the T-1 is there; but its always good to keep acls to minimum)

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