diff --git a/redhat/quagga.spec.in b/redhat/quagga.spec.in
index e45ec1f..dce0308 100644
--- a/redhat/quagga.spec.in
+++ b/redhat/quagga.spec.in
@@ -1,21 +1,26 @@
 # configure options
-%define 	with_snmp	1
-%define		with_vtysh	1
-%define		with_ospf_te	1
-%define		with_nssa	1
-%define		with_opaque_lsa 1
-%define		with_tcp_zebra	0
-%define		with_vtysh	1
-%define		with_pam	1
-%define		with_ipv6	1
-%define		with_ospfclient 1
-%define		with_ospfapi	1
-%define		with_irdp	1
-%define		with_isisd	0
-%define		with_shared	1
-%define		with_multipath	64
-%define		quagga_user	quagga
-%define		vty_group	quaggavty
+#
+# Some can be overriden on rpmbuild commandline with:
+# rpmbuild --define 'variable value'
+#
+
+%{!?with_snmp:		%define 	with_snmp	1 }
+%{!?with_vtysh:		%define		with_vtysh	1 }
+%{!?with_ospf_te:	%define		with_ospf_te	1 }
+%{!?with_nssa:		%define		with_nssa	1 }
+%{!?with_opaque_lsa:	%define		with_opaque_lsa 1 }
+%{!?with_tcp_zebra:	%define		with_tcp_zebra	0 }
+%{!?with_vtysh:		%define		with_vtysh	1 }
+%{!?with_pam:		%define		with_pam	1 }
+%{!?with_ipv6:		%define		with_ipv6	1 }
+%{!?with_ospfclient:	%define		with_ospfclient 1 }
+%{!?with_ospfapi:	%define		with_ospfapi	1 }
+%{!?with_irdp:		%define		with_irdp	1 }
+%{!?with_isisd:		%define		with_isisd	0 }
+%{!?with_shared:	%define		with_shared	1 }
+%{!?with_multipath:	%define		with_multipath	64 }
+%{!?quagga_user:	%define		quagga_user	quagga }
+%{!?vty_group:		%define		vty_group	quaggavty }
 
 # path defines
 %define		_sysconfdir	/etc/quagga
@@ -30,8 +35,8 @@
 %define		_localstatedir	/var/run/quagga
 
 # misc internal defines
-%define         quagga_uid      92
-%define         quagga_gid      92
+%{!?quagga_uid:		%define         quagga_uid      92 }
+%{!?quagga_gid:		%define         quagga_gid      92 }
 %define		daemon_list	zebra ripd ospfd bgpd
 
 %if %{with_ipv6}
@@ -49,7 +54,7 @@
 %define		all_daemons	%{daemon_list} %{daemonv6_list} %{daemon_other} watchquagga
 
 # allow build dir to be kept
-%define		keep_build	0
+%{!?keep_build:		%define		keep_build	0 }
 
 Summary: Routing daemon
 Name:		quagga