| This target is only valid in the |
| .B nat |
| table, in the |
| .B POSTROUTING |
| chain. It should only be used with dynamically assigned IP (dialup) |
| connections: if you have a static IP address, you should use the SNAT |
| target. Masquerading is equivalent to specifying a mapping to the IP |
| address of the interface the packet is going out, but also has the |
| effect that connections are |
| .I forgotten |
| when the interface goes down. This is the correct behavior when the |
| next dialup is unlikely to have the same interface address (and hence |
| any established connections are lost anyway). It takes one option: |
| .TP |
| .BR "--to-ports " "\fIport\fP[-\fIport\fP]" |
| This specifies a range of source ports to use, overriding the default |
| .B SNAT |
| source port-selection heuristics (see above). This is only valid |
| if the rule also specifies |
| .B "-p tcp" |
| or |
| .BR "-p udp" . |