ExtremeWare Software 7.3.0 Command Reference Guide
419
8
NAT Commands
This chapter covers the following topics:
•
Configuring VLANs for Network Address Translation (NAT)
•
Configuring NAT translation rules
•
Displaying NAT settings
NAT is a feature that allows one set of IP addresses, typically private IP addresses, to be converted to
another set of IP addresses, typically public Internet IP addresses. This conversion is done transparently
by having a NAT device (any Extreme Networks switch using the “
i
” chipset) rewrite the source IP
address and layer 4 port of the packets.
You can configure NAT to conserve IP address space by mapping a large number of inside (private)
addresses to a much smaller number of outside (public) addresses.
In implementing NAT, you must configure at least two separate VLANs involved. One VLAN is
configured as inside, and corresponds to the private IP addresses you would like to translate into other
IP addresses. The other type of VLAN is configured as outside, which corresponds to the public
(probably Internet) IP addresses you want the inside addresses translated to. The mappings between
inside and outside IP addresses are done using rules that specify the IP subnets involved and the
algorithms used to translate the addresses.
NOTE
The NAT modes in ExtremeWare only support translating traffic that initiates from inside addresses.
NAT rules are associated with a single outside VLAN. Multiple rules per outside VLAN are allowed.
The rules take effect in the order they are displayed using the
show
command. Any number of inside
VLANs can use a single outside VLAN, assuming that you have created proper rules. Similarly, a single
inside VLAN can use any number of different outside VLANs, assuming that the rules and routing are
set up properly.
TCP and UDP layer 4 ports, in combination with the IP addresses, form a unique identifier which
allows hosts (as well as the NAT switch) to distinguish between separate conversations. NAT operates
by replacing the inside IP packet’s source IP and layer 4 port with an outside IP and layer 4 port. The
NAT switch maintains a connection table to map the return packets on the outside VLAN back into
their corresponding inside sessions.
Summary of Contents for ExtremeWare 7.3.0
Page 54: ...54 ExtremeWare Software 7 3 0 Command Reference Guide Contents...
Page 104: ...104 ExtremeWare Software 7 3 0 Command Reference Guide Commands for Accessing the Switch...
Page 378: ...378 ExtremeWare Software 7 3 0 Command Reference Guide FDB Commands...
Page 418: ...418 ExtremeWare Software 7 3 0 Command Reference Guide QoS Commands...
Page 436: ...436 ExtremeWare Software 7 3 0 Command Reference Guide NAT Commands...
Page 600: ...600 ExtremeWare Software 7 3 0 Command Reference Guide SLB Commands...
Page 968: ...968 ExtremeWare Software 7 3 0 Command Reference Guide Security Commands...
Page 1002: ...1002 ExtremeWare Software 7 3 0 Command Reference Guide EAPS Commands...
Page 1126: ...1126 ExtremeWare Software 7 3 0 Command Reference Guide ESRP Commands...
Page 1392: ...1392 ExtremeWare Software 7 3 0 Command Reference Guide IGP Commands...
Page 1478: ...1478 ExtremeWare Software 7 3 0 Command Reference Guide BGP Commands...
Page 1556: ...1556 ExtremeWare Software 7 3 0 Command Reference Guide IP Multicast Commands...
Page 1600: ...1600 ExtremeWare Software 7 3 0 Command Reference Guide IPX Commands...
Page 1616: ...1616 ExtremeWare Software 7 3 0 Command Reference Guide ARM Commands...
Page 1694: ...1694 ExtremeWare Software 7 3 0 Command Reference Guide PoS Commands...
Page 1750: ...1750 ExtremeWare Software 7 3 0 Command Reference Guide T1 E1 and T3 WAN Commands...
Page 1856: ...1856 ExtremeWare Software 7 3 0 Command Reference Guide MPLS Commands...
Page 1898: ...1898 ExtremeWare Software 7 3 0 Command Reference Guide High Density Gigabit Ethernet Commands...
Page 1938: ...1938 ExtremeWare Software 7 3 0 Command Reference Guide Power Over Ethernet Commands...
Page 1988: ...1988 ExtremeWare Software 7 3 0 Command Reference Guide H VPLS Commands...
Page 2106: ...2106 ExtremeWare Software 7 3 0 Command Reference Guide Wireless Commands...
Page 2132: ...2132 ExtremeWare Software 7 3 0 Command Reference Guide Configuration and Image Commands...
Page 2236: ...2236 ExtremeWare Software 7 3 0 Command Reference Guide Troubleshooting Commands...
Page 2254: ...2254 ExtremeWare Software 7 3 0 Command Reference Guide Index of Commands...