IT people must also be on their guard against unknown callers posing as vendors. In general, a company should consider having specific people designated as the contacts for each technology vendor, with a policy in place that other employees will not respond to vendor requests for information about or changes to any telephone or computer equipment. That way, the designated people become familiar with the vendor personnel who call or visit, and are less likely to be deceived by an imposter. If a vendor calls even when the company does not have a support contract, that should also raise suspicions.