CalAmp Dataradio Sentry 4G 900 User Manual page 25

DNS Auto: The command enables/disables the Sentry 4G DNS server. Except in special
cases, this should always be enabled.
5.4.1.3 DHCP Server Configuration
DHCP Server: (Dynamic Host Configuration Protocol) A protocol used by client devices that
are connected to the LAN port of this device to automatically obtain an IP address assigned
by this server/router. Selecting Enable will configure this device to assign IP addresses to
client devices taken from a pool specified by the values entered in DHCP start range and
DHCP end range. If DHCP is disabled, the information must be entered manually on all PCs.
DHCP Start IP Address/End IP Address: Sets the range of IP addresses assigned to the
PCs. The user can limit the number of devices allowed on the network by limiting the range of
IP addresses.
IMPORTANT NOTE:
The addresses in this range must be on the same subnet as the Ethernet IP
IMPORTANT NOTE:
The Ethernet IP should not be in the DHCP range.
DHCP Lease Time: Number that dictates the length of time a device on the LAN can hold an
IP address. In most cases, this should be set to the maximum (default value) of 86400. If
this value is set too low, it can cause network connectivity problems.
Domain Name Suffix: The DNS suffix to be assigned by the DHCP server.
Preferred DNS Server: IP address of the preferred DNS server.
Alternate DNS Server: IP address of the alternate DNS server.
5.4.1.4 Disabling DHCP server
When DHCP server is enabled, any PC with physical access to the Sentry 4G Ethernet port will
be assigned an IP address and have access to browse the Internet. This may cause security
problems. Disabling DHCP server will allow the user to control which PCs have the ability to
connect through the Sentry 4G unit. If changes are made to the network settings, be sure to
keep a record of the changes for future use.
Disabling DHCP server is performed on the LAN settings page

select Disable, then click Save.
IMPORTANT NOTE:
This also disables DNS Masquerading. Disabling DHCP server will remove all values
in the DHCP and DNS sections. Record all values in these fields prior to disabling in
case you are required to go back to the original configuration.
To improve security, change the Ethernet IP of the Sentry 4G unit from the default

setting.
IMPORTANT NOTE:
If the DHCP server is disabled, and you do not have a record of the Ethernet IP,
you will not be able to login to the Sentry 4G home page.
On the network setting page of each PC set the following
– IP address: Set a unique address on the same subnet as the Sentry 4G router
– Subnet Mask: Set to the same value as the Sentry4G's Ethernet Subnet Mask field
– Default Gateway: Ethernet IP of the Sentry 4G router
– Preferred DNS: Ethernet IP of Sentry 4G router
001-9193-001 Version 1 Page 25 of 48
CONFIGURATION
Under the DHCP section,
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Sentry 4G 900 TM User Manual