ZyXEL Communications P-1100 - Manual (Page 82)

Prestige 1100 Internet Access Router
8-10 Filter Configuration
The following diagram illustrates the logic flow of an IP filter.
Packet
into IP Filter
Matched
Matched
Yes
Action Matched
Action Not Matched
More?
No
Filter Active?
Check
IP Protocol
Drop
Drop Packet Accept Packet
Drop Forward Check Next Rule
Check Next Rule
Check Next Rule
Forward
Not Matched
Yes
No
Check Src
IP Addr
Apply SrcAddrMask
to Src Addr
Matched
Check Dest
IP Addr
Apply DestAddrMask
to Dest Addr
Not Matched
Not Matched
Check Src &
Dest Port
Matched
Not Matched
Figure 8-6 Executing an IP Filter