diff -Nru netcfg-2.7.1.orig/src/connections/ethernet netcfg-2.7.1/src/connections/ethernet
--- netcfg-2.7.1.orig/src/connections/ethernet	2012-03-19 20:01:21.000000000 +0100
+++ netcfg-2.7.1/src/connections/ethernet	2012-03-27 12:37:49.933978670 +0200
@@ -22,9 +22,11 @@
         fi
     fi
 
+    SYSCTL_INTERFACE="${INTERFACE/.//}"
+
     # Disable IPv6 before the interface to prevent SLAAC
     if [[ "$IP6" == "no" ]]; then
-        sysctl -q -w "net.ipv6.conf.$INTERFACE.disable_ipv6=1"
+        sysctl -q -w "net.ipv6.conf.$SYSCTL_INTERFACE.disable_ipv6=1"
     fi
 
     report_debug ethernet_iproute_up ifup
@@ -138,7 +140,7 @@
         [[ -d "/proc/sys/net/ipv6" ]] || modprobe ipv6
         ;;
     no)
-        [[ -d "/proc/sys/net/ipv6" ]] && sysctl -q -w "net.ipv6.conf.$INTERFACE.accept_ra=0"
+        [[ -d "/proc/sys/net/ipv6" ]] && sysctl -q -w "net.ipv6.conf.$SYSCTL_INTERFACE.accept_ra=0"
         ;;
     "")  # undefined IP6 does not prevent RA's from being received -> nop
         ;;
@@ -152,10 +154,10 @@
         if [[ -x /usr/sbin/dhclient ]]; then
             _DHCLIENT_PIDFILE="/run/dhclient6-${INTERFACE}.pid"
             if [[ "$IP6" = "dhcp-noaddr" ]]; then
-                sysctl -q -w "net.ipv6.conf.$INTERFACE.accept_ra=1"
+                sysctl -q -w "net.ipv6.conf.$SYSCTL_INTERFACE.accept_ra=1"
                 DHCLIENT6_OPTIONS="-S ${DHCLIENT6_OPTIONS}"
             else
-                sysctl -q -w "net.ipv6.conf.$INTERFACE.accept_ra=0"
+                sysctl -q -w "net.ipv6.conf.$SYSCTL_INTERFACE.accept_ra=0"
             fi
             rm -r ${_DHCLIENT_PIDFILE} &>/dev/null
             report_debug ethernet_up dhclient -6 -q -e TIMEOUT="${DHCP_TIMEOUT:-10}" -pf ${_DHCLIENT_PIDFILE} "$INTERFACE"
@@ -169,10 +171,10 @@
         fi
         ;;
     stateless)
-        sysctl -q -w "net.ipv6.conf.$INTERFACE.accept_ra=1"
+        sysctl -q -w "net.ipv6.conf.$SYSCTL_INTERFACE.accept_ra=1"
         ;;
     static)
-        sysctl -q -w "net.ipv6.conf.$INTERFACE.accept_ra=0"
+        sysctl -q -w "net.ipv6.conf.$SYSCTL_INTERFACE.accept_ra=0"
         if [[ -n "$ADDR6" ]]; then
             for addr in "${ADDR6[@]}"; do
                 report_debug ethernet_iproute_up ip -6 addr add "$addr" dev "$INTERFACE"