The only problem with -W is that it is not available everywhere yet: RHEL6 defaults to OpenSSH 5.3, while -W was introduced in 5.4. Thankfully EL7 comes with Op

The only problem with -W is that it is not available everywhere yet: RHEL6 defaults to OpenSSH 5.3, while -W was introduced in 5.4. Thankfully EL7 comes with OpenSSH 6.4 (and a kernel newer than 2.6.32!).