Verizon MI424WR User Manual
Page 149
144
Wireless Broadband Router User Manual
The matching of packets by rules is connection-based, known as Stateful Packet
Inspection (
SPI
), using the Router’s firewall mechanism. Once a packet matches a
rule, all subsequent packets with the same attributes receive the same
Q
o
S
param-
eters, both inbound and outbound. Connection-based
Q
o
S
also allows inheriting
Q
o
S
parameters by some of the applications that open subsequent connections.
For instance,
Q
o
S
rules can be defined on
SIP
, and the rules will apply to both con-
trol and data ports (even if the data ports are unknown). Applications that support
such inheritance have an
ALG
in the firewall. They are:
s
SIP
s
MSN
Messenger/Windows Messenger
s
TFTP
s
FTP
s
MGCP
s
H
.323
s
s
PPTP
s
IPS
ec