CBV383Z4S-N300
Cable Modem
User’s Manual
12
4.4.4 Port Filtering
The Port Filtering page allows you to enter ranges of destination ports
(applications) that you don’t want your LAN PCs to send packets to. Any
packets your LAN PCs send to these destination ports will be blocked. For
example, you could block access to worldwide web browsing (HTTP port 80)
but still allow email service (SMTP port 25 and POP3 port 110).
To enable port filtering, enter the
Start port
and
End port
for each range.
Then select its protocol form the drop-down list and check the
Enable
box,
and click
Apply
button. To block only one port, set both Start and End ports
the same.
4.4.5 Forwarding
For communications between LAN and WAN, the CBV383Z4S-N300
normally only allows you to originate an IP connection with a PC on the WAN;
it will ignore attempts of the WAN PC to originate a connection onto your PC.
This protects you from malicious attacks from outsiders. However, sometimes
you may wish for anyone outside to be able to originate a connection to a
particular PC on your LAN if the destination port (application) matches one
you specify.
The Forwarding page allows you to specify up to 10 rules.
