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.
Who is Participating?
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.
The Firewall Audit Checklist

Preparing for a firewall audit today is almost impossible.
AlgoSec, together with some of the largest global organizations and auditors, has created a checklist to follow when preparing for your firewall audit. Simplify risk mitigation while staying compliant all of the time!

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.
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

All Courses

From novice to tech pro — start learning today.