Expanding iprange to 23 bit mask



  • Hi All,

    Not sure if this is a right place to post it but I will start here.

    My pfSense is acting as Router / Firewall / Gateway.

    Currently the LAN interface is set with /24 bit mask on 192.168.1.0 network and I am looking to expand IP range to 23 bit mask expanding to192.168.2.0 address range.

    Is there anything else that needs to be done other then changing the mask to 23 bit in LAN interface settings (so in my case it would be 192.168.1.0 /23?

    I did above but cannot ping any host in 192.168.2.0 range of addresses from 192.168.1.0 and the other way around as well.

    Thank you.



  • A /23 always extends over 2 adjacent /24 ranges, starting with an even, followed by an odd number. e.g.
    192.168.0.0/24 and 192.168.1.0/24 together = 192.168.0.0/23

    You can't make a subnet that has just 192.168.1.0/24 and 192.168.2.0/24 together - the binary arithmetic does not work out.

    You can make 192.168.0.0/22 which will be 4 /24 subnets together, and includes both the ranges you are interested in:

    192.168.0.0/24 +
    192.168.1.0/24 +
    192.168.2.0/24 +
    192.168.3.0/24 =
    192.168.0.0/22




  • LAYER 8 Global Moderator

    As phil pointed out while /22 gives you the 192.168.2.0 to work with – Your other option would of been to just use 192.168.0 vs 192.168.2 -- so when you changed your pfsense lan IP from 192.168.1.x/24 to 192.168.1.x/23 you would of been fine talking to devices using 192.168.0.x/23 where pfsense IP would just be in the second /24 in the /23 mask.


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