Configure the desired Guest I-SID.
default eapol port {slot/port[/sub-port][-slot/port[/sub-port]][,...][slot/all][all]} guest-isid <1-16000000>
eapol port {slot/port[/sub-port][-slot/port[/sub-port]][,...][slot/all][all]} guest-isid <1-16000000>
no eapol guest-isid
None
GigabitEthernet Interface Configuration