How to disable version 1 and version 2c in snmpd?

Comment out the lines that start with com2sec, group, and access in snmpd.conf, e.g:

 [root@sandbox snmp]# cat snmpd.conf
 #com2sec notConfigUser  default       public
 #group   notConfigGroup v1           notConfigUser
 #group   notConfigGroup v2c           notConfigUser
 view    systemview    included   .1.3.6.1.2.1.1
 view    systemview    included   .1.3.6.1.2.1.25.1.1
 #access  notConfigGroup ""      any       noauth    exact  systemview none none
 #com2sec local     0.0.0.0/0        publicrw
 #com2sec mynetwork 0.0.0.0/0        publicro
 #group MyRWGroup  any        local
 #group MyROGroup  any        mynetwork
 view all    included  .1                               80
 view mib2   included  .iso.org.dod.internet.mgmt.mib-2 fc
 #access MyROGroup ""      any       noauth    0      all    none   none
 #access MyRWGroup ""      any       noauth    0      all    all    all
 syslocation Unknown (edit /etc/snmp/snmpd.conf)
 syscontact Root <root@localhost> (configure /etc/snmp/snmp.local.conf)
 rwuser readonly

[root@sandbox snmp]# snmpwalk -v1 -c public localhost
Timeout: No Response from localhost

[root@sandbox snmp]# snmpwalk -v2c -c public localhost
Timeout: No Response from localhost

[root@sandbox snmp]# snmpwalk -v 3 -n '' -l authPriv -u "readonly" -A "readonly" -X "readonly" localhost IF-MIB::ifName
IF-MIB::ifName.1 = STRING: lo 
IF-MIB::ifName.2 = STRING: eth0
IF-MIB::ifName.3 = STRING: eth1