Firewall filters won't get applied if we ignore the case-sensitive nature of Prefix lists.

Firewall filters won't get applied if we ignore the case-sensitive nature of Prefix lists.

On Juniper SRX devices (Junos OS), prefix-list names are case-sensitive. The system treats names with different letter casing as separate and unrelated objects.

Example:

user@host> show configuration firewall

family inet {

  filter Blocked_IPs {

    term 1 {

      from {

        prefix-list {

          IP.List;

        }

      }

      then {

        discard;

      }

    }

    term default {

      then accept;

    }

  }

If the prefix list starts name is IP.list the above firewall filter would not match 

user@host> show configuration | display set | match prefix-list

set policy-options prefix-list IP.list x.x.x.x/23

set policy-options prefix-list IP.list x.x.x.x/24

Key Clarification

Prefix lists can be named using any combination of uppercase and lowercase letters; however, the name must be referenced with exact case matching wherever it is used.