I got a phone call and didn't recognize the number, so I ignored it as usual. They left a message, it was someone from some company who noticed my profile on LinkedIn and acknowledged that I work at my current company and asked if I was interested in exploring other opportunities. I'm not really interested in exploring opportunities. This is the first unsolicited call like this that I've gotten while currently employed, so I'm not sure what the etiquette is. I have a guess, but want to confirm.