Bind user to the IP they are assigned to
I put this into security, although it is also good for networking
Currently there is no possibility, known to me and CPanel Support, to force
clients to use their own IP address for outgoing connections (Scripts,
CURL etc.) as CPanel is not involved in any routing issues.
Clients on the shared main IP can bind outgoing connections to any dedicated IP on
the same server (they know about) on the same subnet or Gateway (on MAC
based routing). Needless to say that this is horrible securitywise as
they could identify themselve as someone else on abusive behaviour.
I have a setup with one shared IP with many clients and one dedicated IP,
which is used internally and is also used for licensing CPanel and
other stuff. I was forced to set a default route src to the dedicated
IP. No surprise, now ALL traffic leaves the server from the dedicated
one, even if a shared client issued the connection.
If I do not set a default route to the dedicated IP ALL outgoing traffic is routed over the shared main IP.
So it would be a good idea to enforce that clients can not use other IPs which are not assigned to them.