The default virtual MAC address used by HSRP (Hot Standby Router Protocol) group 30 is "00:00:0c:07:ac:1e". HSRP uses a well-known MAC address format which includes the HSRP group number in hexadecimal. For group 30, the hexadecimal equivalent is "1e", hence the virtual MAC address ends with "ac:1e". References: Cisco Community discussion on HSRP Virtual MAC Format.