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Ip addresses and dhcp, Time and ntp – Allied Telesis AT-8700XL Series Switch User Manual

Page 42

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42

AT-8700XL Series Switch User Guide

Software Release 2.6.1

C613-02030-00 REV B

IP Addresses and DHCP

Problem

The switch is enabled as a DHCP server, but cannot assign an IP address to a
host.

Solution

Reboot the host machine.

Check the host’s TCP/IP settings, to make sure that the host is set to obtain
its IP address dynamically:

In Windows 95/98, click Settings > Control Panel > Network. Select TCP/
IP and click Properties. Click Obtain an IP address automatically.

In Windows 2000, click Settings > Control Panel > Network and Dial-up
Connections > Local Area Connection > Properties. Select Internet
connection (TCP/IP) and click Properties. Click Obtain an IP address
automatically

.

Check that the switch’s link to the LAN is functioning, by checking the
interface status (Monitoring) and that the link LED is lit (see “Traffic Flow
on page 41).

Time and NTP

Diagnosis

The switch’s time is displayed on the Configuration > System > Time tab. It
will also be included in log packets.

Problem

The switch’s time does not change, even though you entered the correct time.

Solution

Changing the time is a 3-step process. Select Configuration > System > Time.
First, enter a time that is very shortly in the future (e.g. 20 seconds later than
the current time). Then check Set time. Then wait until precisely the time you
have entered, and click Apply.

Problem

The switch is not assigning the time to devices on the LAN.

Solutions

Check NTP is enabled (Configuration > System > Time).

Check that the NTP peer’s IP address is entered correctly.

Check that the NTP peer can reach the switch, by pinging the switch from
the NTP peer.

Check that the switch’s link to the LAN is functioning. See “Traffic Flow” on
page 41.

Problem

The switch’s clock does not synchronise with the NTP peer.

Solution

The switch’s clock can only synchronise with the NTP peer if its initial time
is similar to the NTP peer’s time (after setting the UTC offset). Manually
set the switch’s time so that it is approximately correct, and enable NTP
again.

Check that the UTC offset is correct.

Problem

The switch’s time is incorrect, even though it assigns the correct time to
devices on the LAN.

Solution

The UTC offset is probably incorrect, or needs to be adjusted for the beginning
or end of summer time. To correct this, select Configuration > System > Time
and enter the correct offset.