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Windows Thread, Subnet Mask Change in Technical; Hi we need to expand our IP Address Range from 255.255.252.0 to ? any advice or suggestions on how we ...
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    Grommit's Avatar
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    Subnet Mask Change

    Hi

    we need to expand our IP Address Range from 255.255.252.0 to ?

    any advice or suggestions on how we can change all the fixed IP's onsite ? and Servers, AP, Printers, Onelans, Tills.. etc .. what is the next SN Mask up ?

    Thanks

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    Re: Subnet Mask Change

    Just change the Subnet mask to 255.255.0.0
    Thataway you will not need to change any ip addresses and you gain more

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    Re: Subnet Mask Change

    It would be 255.255.251.0 but this wil only give you another x.1 ~ x.254 addresses but what Paid_peanuts said is probs the best way then you dont have to worry about running out of IPs

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    Re: Subnet Mask Change

    For windows servers with fixed IPs use a netsh script. For other devices use DHCP reservations and change their config accordingly. If they already have reservations delete them and remake.
    Get a subnet calculator to see how many hosts etc to subnet ranges.

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    Re: Subnet Mask Change

    Why do you want to change the subnet mask? you can't have used all the available ips on a range unless you have a network the size of Microsofts?

    Example here we use x.x.10.x for client ip's and to expand it by another 255 we just used x.x.11.x and to expand it further we could use x.x.12.x.

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    zag
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    Re: Subnet Mask Change

    Just change every device to 255.255.252.0, then extend your dhcp range. It should be pretty troublefree.

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    Re: Subnet Mask Change

    Quote Originally Posted by Paid_Peanuts
    Just change the Subnet mask to 255.255.0.0
    Thatway you will not need to change any ip addresses and you gain more
    Only if hes on a subnetted class A or B to start with, in which case he'd still need to change the subnet on every statically assigned device. Plus if hes on a subnetted class A/B chances are hes part of a wider network (ie RBC)

    Quote Originally Posted by timbo343
    It would be 255.255.251.0
    No its not. Its 255.255.248.0, there isnt such thing as a 251 subnet mask.

    Quote Originally Posted by Disease
    Why do you want to change the subnet mask? you can't have used all the available ips on a range unless you have a network the size of Microsofts?
    What, MSs network has a whole 1022 hosts? Wow, alot!



    Im not sure if theres an easy way of doing it tbh, would probably be best in a way anyhow as you will be able to plan all the scopes without concern for current ips.

    Why did you have it subnetted in the first place? Are you part of a bigger network, like part of the council? If so then you cant just change your subnet, it wont work.
    Cant really see any other reason to have a subnetted class A/B than if you are part of a bigger picture, so my bets are on you having to contact the council anyway.


    If your network is just your own private one (no one else connected) i see no reason why not to go with a straight class B now ie 255.255.0.0 but you will still need to change your ips to a network with in this range 172.16.0.0 - 172.31.0.0




    If you need anymore help give me a shout.

    No offense to anyone else whos trying to help but if you arnt sure about what your talking about dont say it, as if he'd followed some of the advice on here he would have ended up with a dead network and im sure his boss(s) would have been happy with him when they came back after summer to find they have no computers and to get it fixed in a timely fation will cost x thousand £££

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    Re: Subnet Mask Change

    I was having a think;

    Give me ALL your details and i may have a solution for you, hopefully one which doesnt involve changing ip address's only the subnet.

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    Re: Subnet Mask Change

    Your subnet is the standard subnet for secondary schools (well certainly around here anyway) so looks like you could be part of a larger network, eg your RBC. Can you confirm whether this is true. If so then changing your subnet is a definite 'no go'.

    Could you also confirm how many IP addresses you need. Your subnet will give you 1022 IPs. Have you really used all these 'cos thats a lot of stuff

    EDIT: sorry to sparky for duplicating the things you posted ops:

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    Re: Subnet Mask Change

    10.0.0.0/255.0.0.0. Future-proof

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    Re: Subnet Mask Change

    Quote Originally Posted by webman
    10.0.0.0/255.0.0.0. Future-proof
    lmao

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    Re: Subnet Mask Change

    Quote Originally Posted by sparkeh
    Your subnet is the standard subnet for secondary schools (well certainly around here anyway) so looks like you could be part of a larger network, eg your RBC. Can you confirm whether this is true. If so then changing your subnet is a definite 'no go'.

    Could you also confirm how many IP addresses you need. Your subnet will give you 1022 IPs. Have you really used all these 'cos thats a lot of stuff

    EDIT: sorry to sparky for duplicating the things you posted ops:

    Its alright, ill let you off.

    For a minute there i thought i was going mad as everyone had seemed to disagree with my way of thinking, good to know im still semi-sane

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    Re: Subnet Mask Change

    Quote Originally Posted by j17sparky
    I was having a think;

    Give me ALL your details and i may have a solution for you, hopefully one which doesnt involve changing ip address's only the subnet.
    Thanks for the input guys..

    192.168.1.1 - 192.168.3.254

    sn 255.255.252.0

    and I am running out of IP addresses as I only have around 1024 IP addresses

    And I need to go to 255.255.248.0 = 2048 Hosts

    or 255.255.240.0 = 4096 hosts

    I am not Sub Netted off of any other Network

    My question was how do I expand the scope as I would have to change the SN mask and it would be OK on the PC's but on the static addresses I would have to manualy change the SN Mask which wuld be a bitch to do..

    Any ideas :-)
    Attached Images Attached Images

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    Re: Subnet Mask Change

    Doesnt using a class b style subnetted private class c address confuse some apps/devices? (Sorry cant think of a better way of putting it )

    Personally id go straight to a private class b range now, you will need to change the subnet mask on all your devices anyway so you may aswell change the ip while your at it.

    No theres no easy way of doing it on anything but PCs.

    Yes it will work afaik but i suspect sooner or later you will find something which doesnt like having a private class c address with a class b mask.

    If you go keep 192.168.x.x id just use 255.255.0.0, even if its just for th3e sake of typing less numbers lol


    Can i ask why you/your school chose that class and mask in the first place

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    sparkeh's Avatar
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    Re: Subnet Mask Change

    Quote Originally Posted by j17sparky
    Doesnt using a class b style subnetted private class c address confuse some apps/devices? (Sorry cant think of a better way of putting it )
    Well I have wondered this before but the RBCs hand out these subnets so I guess its ok (though I strongly suspect our RBC makes its decisions via magic eight-ball). However I work in the Primary phase where 254 IPs is ample so never tested it :P

    Quote Originally Posted by Grommit
    I am not Sub Netted off of any other Network
    So it looks like you are behind a server that hands out private address independent of the RBC? I will echo sparky's question about the choice of subnet - just interested really

    Quote Originally Posted by j17sparky
    Can i ask why you/your school chose that class and mask in the first place



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