1This target is only valid in the
2.B nat
3table, in the
4.B POSTROUTING
5and
6.B INPUT
7chains, and user-defined chains which are only called from those
8chains.  It specifies that the source address of the packet should be
9modified (and all future packets in this connection will also be
10mangled), and rules should cease being examined.  It takes the
11following options:
12.TP
13\fB\-\-to\-source\fP [\fIipaddr\fP[\fB\-\fP\fIipaddr\fP]][\fB:\fP\fIport\fP[\fB\-\fP\fIport\fP]]
14which can specify a single new source IP address, an inclusive range
15of IP addresses. Optionally a port range,
16if the rule also specifies one of the following protocols:
17\fBtcp\fP, \fBudp\fP, \fBdccp\fP or \fBsctp\fP.
18If no port range is specified, then source ports below 512 will be
19mapped to other ports below 512: those between 512 and 1023 inclusive
20will be mapped to ports below 1024, and other ports will be mapped to
211024 or above. Where possible, no port alteration will occur.
22In Kernels up to 2.6.10, you can add several \-\-to\-source options. For those
23kernels, if you specify more than one source address, either via an address
24range or multiple \-\-to\-source options, a simple round-robin (one after another
25in cycle) takes place between these addresses.
26Later Kernels (>= 2.6.11-rc1) don't have the ability to NAT to multiple ranges
27anymore.
28.TP
29\fB\-\-random\fP
30If option
31\fB\-\-random\fP
32is used then port mapping will be randomized through a hash-based algorithm (kernel >= 2.6.21).
33.TP
34\fB\-\-random-fully\fP
35If option
36\fB\-\-random-fully\fP
37is used then port mapping will be fully randomized through a PRNG (kernel >= 3.14).
38.TP
39\fB\-\-persistent\fP
40Gives a client the same source-/destination-address for each connection.
41This supersedes the SAME target. Support for persistent mappings is available
42from 2.6.29-rc2.
43.PP
44Kernels prior to 2.6.36-rc1 don't have the ability to
45.B SNAT
46in the
47.B INPUT
48chain.
49.TP
50IPv6 support available since Linux kernels >= 3.7.
51