3Com Traffix Transcend Traffix Manager, User Manual

Page: 134 / 186

134 A
PPENDIX
D: U
SING THE
S
UBNETS
DB F
ILE
Subnet masks must comply with the primary internet network class types
by covering at a minimum the part of the address that represents the
network bits. In
Table 18 , * is any number between 0 and 255.
Table 18 Subnet Masks
If a subnet mask spans more than one class A/B/C subnet then only the
first entry should be used. For example, if the subnet is 130.99.92 and
the mask is 255.255.252.0, this spans four class A/B/C subnets
(130.99.92, 130.99.93, 130.99.94, and 130.99.95). However, only the
first entry should be added to the file:
When you provide a DNS domain name for a subnet, devices in this
subnet will be placed in this domain, if the DNS lookup fails for a device.
This ensures that these devices appear in the correct group when you use
the DNS grouping.
When Traffix Manager discovers a new IP device on your network, it
performs a DNS lookup for the DNS name of that device. If this lookup
fails, or if your site has no DNS, Traffix Manager will check the SubnetsDB
file to see if the device is in a given subnet. If so, it will assign the DNS
name of the subnet to the device.
If the device is not found in SubnetsDB, then a final check is done to see
if it is in the same subnet as the Traffix Server. If it is, the device is
assigned to the subnet
home-subnet
and the DNS domain is set to that of
the server (if it has one).
You can override this by making sure that there is an entry in the
SubnetsDB file for the subnet of the Traffix Server.
3 When you have added the subnets you require, click OK in the subnet
definition file editor.
Traffix Manager detects changes to the subnet definition file and reloads
it automatically.
Class Description Mask
A 255.*.*.*
B 255.255.*.*
C 255.255.255.*
subnet mask name domain
130.99.92 255.255.252.0 MySubnet acme.com
Network Host Host
1 7 24
0
Host Network
1 1 16 14
1 0
Network Host
1 1 1 8 21
1 0 1