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Syntax of the ACL FileLocate this document in the navigation structure

Lines in the ACL must have the following syntax:

<permit | deny> <ip-address[/mask]> [tracelevel] [# comment]


  • permit = permits a connection, and deny = denies a connection.

  • <ip address>: The IP address must be an IPv4 or IPv6 address in the following form:

    • IPv4: 4 byte, decimal, '.' separated: e.g.

    • IPv6: 16 byte, hexadecimal, ':' separated. '::' is supported

  • <mask>: If a mask is specified, it must be a subnetwork prefix mask:

    • IPv4: 0-32

    • IPv6: 0-128

  • <trace level>: Trace level, with which ACL hits (matches of addresses based on the subnetwork mask) are written to the relevant trace file (default value 2).

  • <# comment>: Comment lines begin with a hash sign (#).

  • The file can contain blank lines.

The rules are checked sequentially from the “top down”. The first relevant rule determines the result (“first match”). If no rule applies, the connection is rejected. To make it obvious, an explicit deny (deny should be entered anyway as the last rule.


permit         # permit client network

permit      # permit server network

permit 1        # screening rule

                           # (learning mode, trace-level 1)

permit 2001:db8::1428:57ab # permit IPv6 host

deny           # deny the rest