Operation Manual

Operating modes and functions
ELSA LANCOM Wireless
46
English
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'off': The DHCP server is permanently disabled.
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'auto': The server is in automode. In this mode, after switching it on, the device
looks for other DHCP server within the local network.
– The device then disables its own DHCP server if any other DHCP servers are
found. This prevents the unconfigured device from assigning addresses not in
the local network when switched on.
– The device then enables its own DHCP server if no other DHCP servers are found.
Whether the DHCP server is active or not can be seen in the DHCP statistics.
The default state is 'auto'.
How are the addresses assigned?
IP address assignment
Before the DHCP server can assign IP addresses to the computers in the network, it first
needs to know which addresses are available for assignment. Three options exist for
determining the available selection of addresses:
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The IP address can be taken from the address pool selected (start address pool to
end address pool). Any valid addresses in the local network can be entered here.
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It then uses the IP address '10.0.0.254' for itself and the address pool '10.x.x.x' for
the assignment of IP addresses in the network. In this state, the DHCP server only
assigns IP addresses and their validity to the computers in the network, but not the
other information.
If only one computer in the network is booted and requests an IP address via DHCP with
its network settings, a device with an activated DHCP module will assign this computer
an address. A valid address is taken from the pool as an IP address. If the computer was
already assigned an IP address at some point in the past, it requests this same address
and the DHCP server attempts to reassign it this address if it has not already been
assigned to another computer.
The DHCP server also checks whether the address selected is still available in the local
network. As soon as the uniqueness of an address has been established, the requesting
computer is assigned the address found.
Network mask assignment
The network mask is assigned in the same way as the address. If a network mask is
entered in the DHCP module, this mask is used for the assignment. Otherwise, the
network mask from the TCP/IP module is used.
Broadcast address assignment
Normally, an address yielded from the valid IP addresses and the network mask is used
for broadcast packets in the local network. In special cases, however (e.g. when using