src_ip
Source IP address.
Syntax
Address ranges can be indicated in conjunction with the srcmask parameter. Only the masked portion of the IP address (corresponding to a one bit in the mask when both are represented in binary) is actually used for comparison; this treated as the IP network number. (The remaining, unmasked, portion is treated as a wildcard.)
A filter rule can thus indicate 'any IP address' by setting the srcmask parameter to 0.0.0.0. (In this case, srcip should also be set to 0.0.0.0 to avoid confusion.)