Enterasys csx400 Manuel De Montage
CSX400 Firmware Support
CyberSWITCH CSX400 and CSX400-DC Installation Guide
2-7
DHCP and NAT
The Dynamic Host Configuration Protocol (DHCP) and Network Address Translation (NAT)
method eliminates the expense of purchasing limited public IP addresses for each client on a local
network, and the need to re-configure a client if it is moved to a different network.
method eliminates the expense of purchasing limited public IP addresses for each client on a local
network, and the need to re-configure a client if it is moved to a different network.
The CSX400 acts as a DHCP server that allows individual clients (PCs, network equipment) to
take turns using a range of private IP addresses (often referred to as local IP addresses), and
provides optional secondary setup features for these clients on a per-port basis. The CSX400
distributes these addresses dynamically assigning a local IP address to an individual client from a
range of 253 available addresses in its table on a first-come-first-served basis. This local IP address
is then “leased” for a predetermined amount of time, which is configured for the particular port.
Each Ethernet port provides DHCP services for one Class C subnet and secondary setup features
for individual clients that support the use of a default gateway, domain name and WINs server.
take turns using a range of private IP addresses (often referred to as local IP addresses), and
provides optional secondary setup features for these clients on a per-port basis. The CSX400
distributes these addresses dynamically assigning a local IP address to an individual client from a
range of 253 available addresses in its table on a first-come-first-served basis. This local IP address
is then “leased” for a predetermined amount of time, which is configured for the particular port.
Each Ethernet port provides DHCP services for one Class C subnet and secondary setup features
for individual clients that support the use of a default gateway, domain name and WINs server.
On the Wide Area Network (WAN) side, the Network Address Translation (NAT) routing method
is used to enable clients assigned with local IP addresses to use the public IP address(es) of the
CSX400 WAN interface(s) to access the WAN.
is used to enable clients assigned with local IP addresses to use the public IP address(es) of the
CSX400 WAN interface(s) to access the WAN.
The NAT method allows several DHCP clients on a sub network to connect to WAN clients by
allowing the DHCP clients to share a single public IP address. When the CSX400 uses NAT, the
NAT method modifies the IP headers and addresses, and the selected fields in upper layer protocol
headers. This is done to replace the hidden local IP addresses from the sub network with one or
more public InterNic assigned IP addresses that can be sent over the outside network on the
CSX400 WAN interfaces. Once the CSX400 is assigned at least one public IP address, over 250 IP
clients can share this address simultaneously using NAT. This public IP address is assigned
statically by the Internet Service Provider (ISP).
allowing the DHCP clients to share a single public IP address. When the CSX400 uses NAT, the
NAT method modifies the IP headers and addresses, and the selected fields in upper layer protocol
headers. This is done to replace the hidden local IP addresses from the sub network with one or
more public InterNic assigned IP addresses that can be sent over the outside network on the
CSX400 WAN interfaces. Once the CSX400 is assigned at least one public IP address, over 250 IP
clients can share this address simultaneously using NAT. This public IP address is assigned
statically by the Internet Service Provider (ISP).
NOTE
A private or “local” network is referred to as a sub network that is using private or
“local” IP addresses. An “outside” network refers to a Wide Area Network (WAN)
commonly known as an Internet, an intranet is an “Internet” in use on a facility or
campus where registered public IP addresses are required.
“local” IP addresses. An “outside” network refers to a Wide Area Network (WAN)
commonly known as an Internet, an intranet is an “Internet” in use on a facility or
campus where registered public IP addresses are required.