This object specifies the ICMP message type to be
configured in ICMP filter group. Setting this object
to '-1' will make the filtering match any ICMP message
type.
Some of the commonly used ICMP Message types are:
0 - Echo Reply
3 - Destination Unreachable
4 - Source Quench
5 - Redirect
8 - Echo
11 - Time Exceeded
12 - Parameter Problem
13 - Timestamp
14 - Timestamp Reply
15 - Information Request
16 - Information Reply
17 - Mask Request
18 - Mask Reply
31 - Conversion Error
32 - Mobile Redirect.