3Com Router WL-602 User Manual

Internet Settings79
DNSDomain Name Service (or Server) is an Internet service that translates 
domain names into IP addresses. Because domain names are alphabetic, 
theyre easier to remember. The Internet however, is really based on IP 
addresses. Every time you use a domain name, a DNS service must 
translate the name into the corresponding IP address. For example, the 
domain name www.example.com might translate to 198.105.232.4.
Figure 61   DNS Screen
If the DNS information is automatically provided...

80CHAPTER 5: CONFIGURING THE ROUTER
Clone MAC addressTo configure the Hostname and Clone MAC Address information for your 
Router, select Internet Settings, then go to the Clone MAC address tab.
Figure 62   Hostname and Clone MAC Address Screen
1Some ISPs require a host name. If your ISP has this requirement, enter the 
host name in the Host Name field.
2Three different ways to configure the WAN MAC Address: 
■If your ISP requires an assigned MAC address, enter the values in the 
WAN MAC address field....

Firewall81
FirewallThis section is for configuration settings of the Router’s firewall function.
Your Router is equipped with a firewall that will protect your network 
from a wide array of common hacker attacks including Ping of Death 
(PoD) and Denial of Service (DoS) attacks. You can turn the firewall 
function off if needed. Turning off the firewall protection will not leave 
your network completely vulnerable to hacker attacks, but 3Com 
recommends that you leave the firewall enabled whenever...

82CHAPTER 5: CONFIGURING THE ROUTER
To enable the firewall function:
1Select the level of protection (High, Medium, or Low) that you desire from 
the Firewall level drop-down menu.
2Click Apply.
■For low and medium levels of firewall protection, refer to Figure 64. 
For low level of firewall protection, the DoS and SPI functions are both 
off. For medium level of firewall protection, DoS in on, but SPI is off. 
■For high level of firewall protection, refer to Figure 65. Both DoS and 
SPI are on for this...

Firewall83
Figure 65   High Level Firewall Protection Screen 
If you select high level of protection, you would have an option to 
configure additional parameters for the firewall. 
■Fragmentation half-open wait - Configures the number of seconds 
that a packet state structure remains active. When the timeout value 
expires, the Router drops the un-assembled packet, freeing that 
structure for use by another packet. 
■TCP SYN wait - Defines how long the software will wait for a TCP 
session to...

84CHAPTER 5: CONFIGURING THE ROUTER
■Total incomplete TCP/UDP sessions HIGH - Defines the rate of new 
unestablished sessions that will cause the software to start deleting 
half-open sessions.
■Total incomplete TCP/UDP sessions LOW - Defines the rate of new 
unestablished sessions that will cause the software to stop deleting 
half-open sessions.
■Incomplete TCP/UDP sessions (per min) HIGH - Maximum number of 
allowed incomplete TCP/UDP sessions per minute.
■Incomplete TCP/UDP sessions (per min) LOW -...

Firewall85
Special ApplicationsSpecial Applications (port triggering) let you choose specific ports to be 
open for specific applications to work properly with the Network Address 
Translation (NAT) feature of the Router. 
Figure 66   Special Applications Screen
A list of popular applications has been included to choose from. Select 
the application from the Popular Applications drop-down menu. Then 
select the row that you want to copy the settings to from the Copy To 
drop-down menu, and click Copy To....

86CHAPTER 5: CONFIGURING THE ROUTER
Virtual ServersThe Virtual servers feature allows you to route external (Internet) calls for 
services such as a web server (port 80), FTP server (Port 21), or other 
applications through your Router to your internal network. Since your 
internal computers are protected by a firewall, machines from the 
Internet cannot get to them because they cannot be seen.
If you need to configure the Virtual Server function for a specific 
application, you will need to contact the...

Firewall87
3Specify the public port that will be seen by clients on the Internet, and the 
LAN port which the traffic will be routed to.
4You can enable or disable each Virtual Server entry by checking or 
unchecking the appropriate Enabled checkbox.
5Click Apply to save the changes for each Virtual Server entry.
DMZIf you have a client PC that cannot run an Internet application properly 
from behind the firewall, you can open the client up to unrestricted 
two-way Internet access. This may be necessary...

88CHAPTER 5: CONFIGURING THE ROUTER
address is not known, or if more than one PC on the Internet will need to 
access the DMZ PC, then set the Public IP Address to 0.0.0.0. 
In the default setting (line 1), Public IP address is set to 0.0.0.0 and it is 
automatically transformed by default WAN IP. We only allow one DMZ 
server to be accessed by public IPs (Many to 1 NAT). If you have more 
than one DMZ server, you have to set a second WAN IP in line 2 and 
define which IP address of DMZ server you would...