docs: update docs with minimized scope of `KUBEVIRT_POSTINBOUND` chain
PR minized the scope of
the `KUBEVIRT_POSTINBOUND` chain.
This commit updates the documentation accordingly.
@@ -308,8 +308,9 @@ target prot opt source destination
KUBEVIRT_POSTINBOUND all -- anywhere anywhere
```
-In the `KUBEVIRT_POSTINBOUND` chain, SNAT is performed: the source IP address
-of the outbound packet is modified to the IP address of the gateway -
+In the `KUBEVIRT_POSTINBOUND` chain, in case the source address is localhost, SNAT is
+performed: the source IP address of the outbound packet is modified to the IP address of
+the gateway -
`10.11.12.1`.
```
