diff --git a/startup.script_linux b/startup.script_linux
index d42de66..5e778d9 100644
--- a/startup.script_linux
+++ b/startup.script_linux
@@ -14,42 +14,42 @@ iocLogInit
 errlog "starting EPICS $(EPICS) at $(IOC_STARTTIME)"
 
 # Set up CA search lists for different networks
-
-# Office (only officicial EPICS subnets, not SLS beamlines!)
-epicsEnvSet CA_129.129.130,"129.129.131.255 129.129.137.255"
-epicsEnvSet CA_129.129.131,"129.129.130.255 129.129.137.255"
-epicsEnvSet CA_129.129.137,"129.129.130.255 129.129.131.255"
-
-# OSFA (SF machine networks)
-# with directed broadcasts
-epicsEnvSet CA_172.26,"172.26.0.255 172.26.2.255 172.26.8.255 172.26.16.255 172.26.24.255 172.26.32.255 172.26.40.255 172.26.110.255 172.26.111.255 172.26.120.255 129.129.242.255 129.129.243.255"
-epicsEnvSet CA_AUTO_172.26,"NO"
-# SwissFEL end stations to machine via gateway
-epicsEnvSet CA_129.129.242,"sf-saresc-cagw:5062"
-epicsEnvSet CA_129.129.243,"sf-saresc-cagw:5062"
-epicsEnvSet CA_129.129.244,"sf-saresc-cagw:5062"
-epicsEnvSet CA_129.129.245,"sf-satesd-cagw:5062"
-epicsEnvSet CA_129.129.246,"sf-satese-cagw:5062"
-epicsEnvSet CA_129.129.247,"sf-satesf-cagw:5062"
-
-# HIPA
-epicsEnvSet CA_172.19,"172.19.10.255 172.19.30.255"
-epicsEnvSet CA_AUTO_172.19,"NO"
-
-# PROSCAN
-epicsEnvSet CA_172.25,"172.25.60.255 172.25.11.255"
-epicsEnvSet CA_AUTO_172.25,"NO" 
-
-# All others can work with the defaults: automatic
-
-# Apply settings dependent on network
-system "/sbin/ifconfig `/sbin/route -n|awk '/^0.0.0.0/{print $8}'`|awk -F '[.: ]+' -vP=epicsEnvSet -vN=NET '/Bcast/{print P,N 1,$9ORS P,N 2,$10ORS P,N 3,$11}/broadcast/{print P,N 1,$13ORS P,N 2,$14ORS P,N 3,$15}'>/tmp/$(IOC).net"
+system "/sbin/ifconfig `/sbin/route -n|awk '/^0.0.0.0/{print $8;exit}'`|awk -F '[: ]+' -vP=epicsEnvSet -vI=IP_ADDR '/Bcast/{print P,I,$4} /broadcast/{print P,I,$3}'>/tmp/$(IOC).net"
 < /tmp/$(IOC).net
 system "rm /tmp/$(IOC).net"
-epicsEnvSet EPICS_CA_ADDR_LIST,"$(CA_$(NET1=).$(NET2=).$(NET3=)=$(CA_$(NET1=).$(NET2=)=))"
-epicsEnvSet EPICS_CA_AUTO_ADDR_LIST,"$(CA_AUTO_$(NET1=).$(NET2=).$(NET3=)=$(CA_AUTO_$(NET1=).$(NET2=)=YES))"
-epicsEnvSet EPICS_CAS_BEACON_ADDR_LIST,"$(CA_BEACON_$(NET1=).$(NET2=).$(NET3=)=$(CA_BEACON_$(NET1=).$(NET2=)=$(EPICS_CA_ADDR_LIST)))"
-epicsEnvSet EPICS_CAS_AUTO_BEACON_ADDR_LIST,"$(CA_AUTO_BEACON_$(NET1=).$(NET2=).$(NET3=)=$(CA_AUTO_BEACON_$(NET1=).$(NET2=)=$(EPICS_CA_AUTO_ADDR_LIST)))"
+
+# Default: automatic
+epicsEnvSet EPICS_CA_AUTO_ADDR_LIST YES
+
+# Office (only officicial EPICS subnets, not SLS beamlines!)
+ifEnvSet $(IP_ADDR) ~129.129.130.* EPICS_CA_ADDR_LIST "129.129.131.255 129.129.137.255"
+ifEnvSet $(IP_ADDR) ~129.129.131.* EPICS_CA_ADDR_LIST "129.129.130.255 129.129.137.255"
+ifEnvSet $(IP_ADDR) ~129.129.137.* EPICS_CA_ADDR_LIST "129.129.130.255 129.129.131.255"
+
+# SwissFEL machine networks
+# with directed broadcasts
+ifEnvSet $(IP_ADDR) ~172.26.* EPICS_CA_ADDR_LIST "172.26.0.255 172.26.2.255 172.26.8.255 172.26.16.255 172.26.24.255 172.26.32.255 172.26.40.255 172.26.110.255 172.26.111.255 172.26.120.255 129.129.242.255 129.129.243.255"
+ifEnvSet $(IP_ADDR) ~172.26.* EPICS_CA_AUTO_ADDR_LIST "NO"
+
+# SwissFEL end stations to machine via gateway
+ifEnvSet $(IP_ADDR) ~129.129.242.* EPICS_CA_ADDR_LIST sf-saresa-cagw:5062
+ifEnvSet $(IP_ADDR) ~129.129.243.* EPICS_CA_ADDR_LIST sf-saresb-cagw:5062
+ifEnvSet $(IP_ADDR) ~129.129.244.* EPICS_CA_ADDR_LIST sf-saresc-cagw:5062
+ifEnvSet $(IP_ADDR) ~129.129.245.* EPICS_CA_ADDR_LIST sf-satesd-cagw:5062
+ifEnvSet $(IP_ADDR) ~129.129.246.* EPICS_CA_ADDR_LIST sf-satese-cagw:5062
+ifEnvSet $(IP_ADDR) ~129.129.247.* EPICS_CA_ADDR_LIST sf-satesf-cagw:5062
+
+# HIPA
+ifEnvSet $(IP_ADDR) ~172.19.* EPICS_CA_ADDR_LIST "172.19.10.255 172.19.30.255"
+ifEnvSet $(IP_ADDR) ~172.19.* EPICS_CA_AUTO_ADDR_LIST NO
+
+# PROSCAN
+ifEnvSet $(IP_ADDR) ~172.25.* EPICS_CA_ADDR_LIST "172.25.60.255 172.25.11.255"
+ifEnvSet $(IP_ADDR) ~172.25.* EPICS_CA_AUTO_ADDR_LIST NO
+
+# Default beacons
+ifEnvSet $(EPICS_CAS_BEACON_ADDR_LIST) ~* EPICS_CAS_BEACON_ADDR_LIST "$(EPICS_CA_ADDR_LIST=)"
+ifEnvSet $(EPICS_CAS_AUTO_BEACON_ADDR_LIST) ~* EPICS_CAS_AUTO_BEACON_ADDR_LIST "$(EPICS_CA_AUTO_ADDR_LIST)"
 
 # set some search paths
 epicsEnvSet EPICS_DRIVER_PATH "bin/R$(EPICS_RELEASE)_$(EPICS_HOST_ARCH):bin:snl:$(EPICS_MODULES=/ioc/modules)"