On Networks N150RM User Manual - Manual (Page 30)

Modem Router Setup
30
N150 Wireless ADSL2+ Modem Router N150RM
• Disable SIP ALG . The Session Initiation Protocol (SIP) Application Level Gateway (ALG)
is enabled by default to optimize VoIP phone calls that use the SIP. You can select this
check box to disable the SIP ALG, which might be useful when running certain
applications.
Default DMZ Server
The default DMZ server feature is helpful when you are using some online games and
videoconferencing applications that are incompatible with Network Address Translation
(NAT). The modem router is programmed to recognize some of these applications and to
work correctly with them, but other applications might not function well. In some cases, one
local computer can run the application correctly if that computer’s IP address is entered as
the default DMZ server.
WARNING:
DMZ servers pose a security risk. A computer designated as the
default DMZ server loses much of the protection of the firewall and
is exposed to exploits from the Internet. If compromised, the DMZ
server computer can be used to attack other computers on your
network.
The router usually detects and discards incoming traffic from the Internet that is not a
response to one of your local computers. Instead of discarding this traffic, you can have the
router forward the traffic to one computer on your network. This computer is called the default
DMZ server.
 To set up a default DMZ server:
1. Select Setup > WAN Setup.
2. Select the Default DMZ Server check box.
3. Type the IP address.
4. Click Apply.
MTU Size
The maximum transmission unit (MTU) is the largest data packet a network device transmits.
When one network device communicates across the Internet with another, the data packets
travel through many devices along the way. If a device in the data path has a lower MTU
setting than the other devices, the data packets have to be split or fragmented to
accommodate the device with the smallest MTU.
The best MTU setting for On Networks equipment is often just the default value. In some
situations, changing the value fixes one problem but causes another. Leave the MTU
unchanged unless one of these situations occurs: