Most antispam engines do a reverse IP lookup and if it is different than what is registered with your domain, it is flagged. The problem is 'live.com' is a universal domain. If somebody was trying to spoof you using s-consult.com most email filters would block it. This is also why its virtually impossible to host an exchange server without a dedicated IP, even if you use something like no-ip.com
(Shameless plug)
This is why our EverSafe and our EverConnect (internet failover to LTE) had alot of thought put into it regarding Exchange server. If your on-premise exchange server was destroyed and we simply spun a copy up in the cloud, most of your outbound email would be flagged as spam because the cloud data center has a different IP than premise. With EverConnect, if you failover to, say Verizon LTE, your Exchange server would appear to be sending from a different IP. We work with clients using some advanced authentication techniques to avoid being flagged as spam in these situations and its why many traditional IT companies don't understand the idiosyncrasies of disaster recovery and failover