Subnet / network question

Our network is working fine with the following configuration
A NSA SonicWALL - DCHP server with LAN ADDRESS

This allows us to use Servers and switches, printers    thru
and our workstations and laptops    thru

We are setting up a remote office via a MPLS and I want those machines as   thru  

When attempting to add a custom route in our SonicWall firewall it says
that the /    is an INVALID subnet
I am NOT a subnet expert don't think  I can learn the math in a day or two.  Any advice appreciated.
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ssisworoConnect With a Mentor Commented:
the solution :
1. you can change mask to
    ==> so you network area increasingly enlarged and grew smaller address
2. you can change network to  (remove the '1' in address area)

your network      => 00001010.00000000.0000010   |   1.00000000
MASK        => 11111111.11111111.1111111   |   0.00000000
                                                        -----------------------------------    |
                                                               network area                      |
                                                                                                           |   ----------------
                                                                                                           |   address area
cavp76Connect With a Mentor Commented:
For -  should be (/24 subnet)
RKinspConnect With a Mentor Commented:
Bit checking.

254 means that your last significant bit is not part of the subnet, so it cannot be 1. (5 has a 1 on the last significant bit).


Good luck.
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cavp has it better since you are going with to

ssisworoConnect With a Mentor Commented:
just convert to binary..
here the example :

                    decimal                    binary
ADDRESS =             => 00001010.00000000.00000000.00000001
MASK       =   => 11111111.11111111.11111110.00000000
                           your network   00001010.00000000.0000000                         ===> 10.0.0
                           your address                                                   0.00000001      ===>  1

the problem is :

your network      => 00001010.00000000.00000101.00000000
MASK        => 11111111.11111111.11111110.00000000
                                                                                                        1 <==== of course this invalid
                                                                                                                     (must be 0)

Or get a IP/Subnet Mask calculator...Boson Utilities ;)
note :
if you want 2 machines or more to communicate, must be in a network. unless you have a router to bridge between different network.
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