Problem with fine-grained CIDR notation (USG Flex 40)

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flurvere
flurvere Posts: 2 image  Freshman Member
edited 1:11AM in Security

The security policies seems to have a problem understanding CIDR notations from /27 and up (or is it down?).

The case in hand is a number of servers in the 192.168.17.96 - 192.168.17.103 range, i.e. 192.168.17.96/29.
But that doesn't work. Neither does 192.168.17.96/28, nor 192.168.17.96/27.

I have to go all the way to /26 (192.168.17.64/26) to get things working properly, or the old-fashioned span 192.168.17.96-192.168.17.103, if I want to keep it a bit tighter.

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  • Zyxel_Melen
    Zyxel_Melen Posts: 4,112 image  Zyxel Employee
    Zyxel Certified Network Engineer Level 1 - Switch Zyxel Certified Network Administrator - Switch Zyxel Certified Network Administrator - Nebula Zyxel Certified Sales Associate

    Hi @flurvere

    192.168.17.96/29 or /28 or /27, the 192.168.17.96 will not in the usable IP range.

    image.png

    If the CIDR is /26, .96 is in the usable ip range.

    image.png

    You can try to create the range address object for this range.

    image.png
    Zyxel Melen


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