P100IH ISDN Router
9-12
Filter Configuration
P a c k e t
into IP Filter
M a t c h e d
M a t c h e d
Y e s
A c t i o n M a t c h e d
A c t i o n N o t M a t c h e d
M o r e ?
N o
Filter Active?
C h e c k
IP Protocol
D r o p
D r o p P a c k e t
A c c e p t P a c k e t
D r o p
F o r w a r d
C h e c k N e x t R u l e
C h e c k N e x t R u l e
C h e c k N e x t R u l e
F o r w a r d
N o t M a t c h e d
Y e s
N o
C h e c k S r c
I P A d d r
A p p l y S r c A d d r M a s k
to Src Addr
M a t c h e d
C h e c k D e s t
I P A d d r
A p p l y D e s t A d d r M a s k
to Dest Addr
N o t M a t c h e d
N o t M a t c h e d
C h e c k S r c &
Dest Port
M a t c h e d
N o t M a t c h e d
Figure 9-8 Executing an IP Filter
