Page 45
Settings
– Advanced Feature
External Filters
Configuration
Block Selected ICMP Types
– These settings determine whether or not
this device should respond to ICMP requests received from the WAN port.
If checked, the selected packet types are blocked. Otherwise, the packets
are accepted.
Echo Request / Information Request / Timestamp / Address Mask
Request :
The ICMP standard (RFC 792) also specifies timestamp
request, information request, and address mask request packets as codes
13, 15, and 17, respectively. While the ostensible purpose for these
queries is to learn information such as address masks and current times,
they can easily be used for host discovery. A system that replies is up and
available. A timestamp reply (ICMP code 14) or address mask (code 18)
discloses that the host is available
DNS Loopback
Used when you have some servers on the LAN and their domain names have
already been registered on public DNS. To avoid DNS loop back problems,
please enter the following fields:
Domain Name
– Enter the domain name specified by you for the local
server.
Private IP
– Enter the private IP address of your local server.
Application
IDENT Port
– Port 113 is associated with the Internet's (Identification /
Authentication) service. When a client program in your computer contacts a
remote server for services such as POP, IMAP, SMTP, that remote server
sends back a query to the "Ident" server running in many systems listening
for these queries on port 113. This means that hackers can probe port 113
as a rich source of your personal information. The default value of this
check box is “Disable”
SMTP Binding
– Unless you are using E-mail accounts from different ISPs
on each port, you can ignore these settings.
Some ISPs configure their E-mail Servers so they will not accept E-mail from
IP addresses not allocated by them. If you are using accounts from different
ISPs, sending E-mail over the wrong WAN port may result in the mail not being
accepted. In this case, you can use these settings to correct the problem:
-Enable
– If enabled, the WAN port you specify below will be used for all
outgoing SMTP traffic. If not enabled, either WAN ports will be used.
-WAN
– Select the desired WAN port to be bound.
IPSec Passthrough
– Enable/Disable IPSec passthrough, and designate it
to a WAN port. By default IPSec passthrough is
“Enable
PPTP Passthrough
– Enable/Disable PPTP passthrough, and designate it
to a WAN port. By default PPTP passthrough is
“Enable
