Draytek Vigor2133 User Manual page 58

MTU
TTL
PPP/MP Setup
IP Address Assignment
Method (IPCP)
46

Ping Retry – Type the number of times that the system is
allowed to execute the PING operation before WAN
disconnection is judged.
It means Max Transmit Unit for packet.
Path MTU Discovery – It is used to detect the maximum MTU
size of a packet not to be segmented in specific transmit
path.
Click Detect to open the following dialog.
Path MTU to – Type the IP address as the specific

transmit path.
MTU size start from - Determine the starting point

value of the packet.
MTU reduce size by – It determines the decreasing size

of MTU value. For example, the number specified in
this field is "8". The maximum MTU size is "1500".
After clicking the "detect" button, the system will
calculate and get the suitable MTU value such as 1500,
1492, 1484 and etc., automatically.
Detect – Click it to detect a suitable MTU value

Accept – After clicking it, the detected value will be

displayed in the field of MTU.
Change the TTL value – Enable or disable the TTL (Time to
Live) for a packet transmitted through Vigor router.
Enable - TTL value will be reduced (-1) when it passess
through Vigor router. It will cause the client, accessing
Internet through Vigor router, be blocked by certain ISP
when TTL value becomes "0".
Disable – TTL value will not be reduced. Then, when a packet
passes through Vigor router, it will not be cancelled. That is,
the client who sends out the packet will not be blocked by
ISP.
PPP Authentication – Select PAP only or PAP or CHAP for
PPP.
Idle Timeout – Set the timeout for breaking down the
Internet after passing through the time without any action.
Usually ISP dynamically assigns IP address to you each time
you connect to it and request. In some case, your ISP
provides service to always assign you the same IP address
whenever you request. In this case, you can fill in this IP
address in the Fixed IP field. Please contact your ISP before
you want to use this function.
WAN IP Alias - If you have multiple public IP addresses and
would like to utilize them on the WAN interface, please use
WAN IP Alias. You can set up to 32 public IP addresses other
than the current one you are using. Type the additional WAN
Vigor2133 Series User's Guide