3Com 3812 Switch User Manual


 
Setting Up Overview 31
CAUTION: To protect your Switch from unauthorized access, you must
change all three default passwords as soon as possible, even if you do not
intend to actively manage your Switch. For more information on default
users and changing default passwords, see “Default Users and
Passwords” on page 44.
IP Configuration You can use one of the following methods to allocate IP information to
your Switch (essential if you wish to manage your Switch across the
network).
Manual IP Configuration
You can choose to configure the IP information yourself. The Switch
remembers the information that you enter until you change it again or
set the configuration method to Automatic.
You should use the Manual IP configuration method if:
you do not have a DHCP server on your network, or
you want to remove the risk of the IP address ever changing, or
your DHCP server does not allow you to allocate static IP addresses.
(Static IP addresses are necessary to ensure that the Switch is always
allocated the same IP information.)
For most installations, 3Com recommends that you configure the Switch
IP information manually. This makes management simpler and more
reliable as it is not dependent on a DHCP server, and eliminates the risk of
the IP address changing.
If you wish to manually enter IP information for your Switch, work
through the “Manually Configuring IP Information”
section on page 32.
Automatic IP Configuration
By default the Switch tries to configure itself with IP information without
requesting user intervention. It tries to obtain an IP address from a DHCP
server on the network.
It may take up to 5 minutes for your Switch to obtain an IP address after
it has been powered up.
When using automatic IP configuration it is important that the IP address
of the Switch is static, otherwise you will not know what the IP address is
and it will be difficult to manage. Most DHCP servers allow static IP
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