There can be many roles within an information services department. In smaller groups these roles may be shared by a few system admins. But within larger groups the maintenance of an IT system is split between several people, one of which is the security administrator.
A lesser known role within computer administration, a security administrator is a specialist in computer and network security, including the administration of security devices such as firewalls.
A common task a security administrator will carry out is the management of the anti-virus software over a system. This software will be updated and checked at regular intervals by the security administrator, in order to maintain the security of a system.
A security administrator will often provide consulting on general security measures. Updating the other members of the information services department on the current operation of the network security, among other status updates of the information system.