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Netwok expansion

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  • Netwok expansion

    Dear All,

    I am using a class C network starting from to Now I have more users and need more than 280 IP connections. Which is the best option for that ?

    Can I switch to Class A or B addressing ? How can I setup my AD, DNS and DHCP for that ?

    Or Can I use a router for VLAN ? Give me a brief for this setup.

    Any other good options which I can follow ?

    Please help,


  • #2
    Re: Netwok expansion

    You could either look at supernetting multiple contiguous Class C networks into a larger one ( or if you feel future growth will warrant it, bite the bullet and change everything to a bigger class B or C network (reconfiguring everything)

    Given you are not much over the Class C size, I suspect supernetting will be the easiest solution although IIRC the simplest way (23-bit subnet mask) will add the 192.168.0.x range to your existing ones. Alterntively you could move to a 22-bit mask and get 192.168.0.x to 192.168.3.x so 1022 addresses
    Tom Jones
    MCT, MCSE (2000:Security & 2003), MCSA:Security & Messaging, MCDBA, MCDST, MCITP(EA, EMA, SA, EDA, ES, CS), MCTS, MCP, Sec+
    IT Trainer / Consultant
    Ossian Ltd

    ** Remember to give credit where credit is due and leave reputation points where appropriate **


    • #3
      Re: Netwok expansion

      Option 1: Switch to a larger network. You could go for an entirely new IP network (like, say,, or create a larger network which also covers your existing address space ( or perhaps

      Option 2: Run two IP networks in parallel. For this to work, it must be possible to assign more than one IP address to the LAN interface on the router, making it the gateway for both networks. The Windows DHCP Service has specific support for such a scenario; it allows for the creation of "superscopes" consisting of two or more regular DHCP scopes.

      I would recommend option 1, as it should be possible to simply switch the netmask on existing equipment with statically assigned addresses and then just alter or recreate the DHCP scope without causing any downtime or interruptions.

      If for some reason you cannot use (or another supernet that covers, you could use DHCP superscopes to gradually move all hosts to a new IP network, again without causing service outages.


      • #4
        Re: Netwok expansion

        As per Ossian, just change the 3rd octet of subnet to 254 or 252. Doing this saves the necessity of having to change all your static IPs, any mappings, VPNs or firewall exclusions that you may presently have.

        Of course if your boss is allowing you to do this during paid overtime then it may be financially to your advantage to make it as difficult and time consuming as you can and change to a 10.x.x.x IP Range.

        Personally I try to make things as easy as I can for myself and changing the Mask is quick and easy.
        Joined: 23rd December 2003
        Departed: 23rd December 2015