Filter
Top Products
ZyXEL X-550 User’s Guide
Advanced
Figure 3-4 WAN- Advanced
Any changes to these options apply to all WAN modes *Static IP/Dynamic IP/PPPoE.
Use These DNS Servers:
This option should be enabled if your ISP requires you to enter the DNS Server information. You will then
be able to enter a primary and secondary DNS server.
Use the default MTU:
If this option is checked (the default case), the router selects the usual MTU settings for the type of WAN
interface in use. If this option is unchecked, the router uses the value of the MTU option (which follows).
MTU:
The Maximum Transmission Unit (MTU) is a parameter that determines the largest packet size (in bytes)
that the router will send to the WAN. If LAN devices send larger packets, the router will break them into
smaller packets. Ideally, you should set this to match the MTU of the connection to your ISP. Typical
values are 1500 bytes for an Ethernet connection and 1492 bytes for a PPPoE connection. If the router's
MTU is set too high, packets will be fragmented downstream. If the router's MTU is set too low, the router
will fragment packets unnecessarily and in extreme cases may be unable to establish some connections. In
either case, network performance can suffer.
WAN Port Speed:
Normally, this is set to "auto". If you have trouble connecting to the WAN, try the other settings.
Respond to WAN Ping:
If you leave this option unchecked, you are causing the public WAN IP address of the router not to respond
to ping commands. Pinging public WAN IP addresses is a common method used by hackers to test whether
your WAN IP address is valid.
WAN Ping Inbound Filter:
Select a filter that controls access as needed for WAN pings. If you do not see the filter you need in the list
3-5