Operation Manual
SFX SERIES USER’S GUIDE
Rev 2.2 56
The following fields can be edited on the Edit SNAT Table page:
Edit Field Description
! Clicking on the “not” (!) check box negates the logic for the immediate edit field to the right of the
check box. For example, !224.1.1.1 for the Source IP would mean all IP packets whose source
IP address is not 224.1.1.1.
Original Source Enter a source IP Address in dotted decimal notation, here if you wish to filter IP packets on
their original source address.
Port Enter a TCP or UDP Port number in any of the three port fields (Original Source, Destination IP,
& New Source if you wish. If a port is specified, you must select a specific protocol (TCP or
UDP).
Destination IP Enter a Destination IP Address in dotted decimal notation, here if you wish to filter IP packets on
their destination IP address.
New Source Enter a New Source IP address that will replace the Original Source IP address, if using SNAT
as the action.
Protocol Enter the IP packet protocol. Options are All Protocols (default), UDP/IP Protocol, or TCP/IP
Protocol. If port numbers are specified in a rule, you must select UDP or TCP.
Action Select an action to be taken for source address translation. The two selections are:
SNAT – replace Original Source IP/Port with New Source IP/Port and continue processing the
packet.
MASQ – Masquerade – replace Original Source IP with the IP address of the network interface
where the IP packet is output. NOTE: A new Source Port number may be automatically
selected by the receiver for UDP & TCP packets.
Options This field is available for “power users”, who wish to enter additional iptables options. Care
must be taken in doing so, and order may matter on entry of options. Some combinations may
not be possible. Consult the Linux iptables manual or tutorial for more information.
In addition to the edit fields there are four table row manipulation keys:
Key Description
Add Add the entered information above the table to the table as the last row.
Remove Delete the selected (highlighted) row.
Up If there is more than one row in the table, move the selected row up one row.
Down If there is more than one row in the table, move the selected row down one row.
Destination NAT
The Destination Network Address Translation (DNAT) submenu is responsible for maintenance of destination IP
address translation, which forms part of the IP packet Filtering Function in the receiver. This table defines up to 25
rules that can be used to filter on various IP packet headers and perform a destination address translation. The rules
in the Destination NAT Table are applied on incoming IP data, typically independent of the network interface the packet
originated from.
Destination NAT is done using options within the Linux iptables facility. More information on iptables can be obtained
from the manual or tutorial online at sites such as http://www.redhat.com. Additionally, you can contact IDC Customer
NOTE
:
The
Original Source
IP/Port and
Destination
IP/Port fields
are optional,
and “Any” is the
implied default
value.