This is the configured address, either a hostname or a literal IP, of the RADIUS server this table entry represents for 802.1X authentication. Because this field accepts either form, an admin relying on a hostname here introduces a DNS dependency into 802.1X authentication that isn't obvious from the table alone; if DNS is down, logins can fail even though the RADIUS server itself is fine. For example, this object might read 10.1.1.50 for a directly-addressed server, or auth-radius.internal if the admin prefers to manage the mapping centrally in DNS.