The index of ACL group used by packet-filter.
If the specified string comprises only digits, it is converted
into a numerical sequence in decimal notation, and regarded as
an ACL group index. If the string is a character string
beginning with an English letter, it is regarded as an ACL
group name.
Group index range and default action:
Basic type: 2000..2999
Advanced type: 3000..3999
MAC type: 4000..4999
User type: 5000..5999