diff --git a/package/ppp/files/etc/ppp/ip-down b/package/ppp/files/etc/ppp/ip-down
index 499dc59d6e..f26cf4db03 100755
--- a/package/ppp/files/etc/ppp/ip-down
+++ b/package/ppp/files/etc/ppp/ip-down
@@ -5,7 +5,7 @@ PPP_TTY="$2"
 PPP_SPEED="$3"
 PPP_LOCAL="$4"
 PPP_REMOTE="$5"
-PPP_IPPARAM="$6"
+PPP_IPPARAM="$(echo $6 | sed 's/\./_/g')"
 export PPP_IFACE PPP_TTY PPP_SPEED PPP_LOCAL PPP_REMOTE PPP_IPPARAM
 [ -z "$PPP_IPPARAM" ] || {
 	env -i ACTION="ifdown" INTERFACE="$PPP_IPPARAM" DEVICE="$PPP_IFACE" PROTO=ppp /sbin/hotplug-call "iface"
diff --git a/package/ppp/files/etc/ppp/ip-up b/package/ppp/files/etc/ppp/ip-up
index ecdd00b1c4..376c87e569 100755
--- a/package/ppp/files/etc/ppp/ip-up
+++ b/package/ppp/files/etc/ppp/ip-up
@@ -5,7 +5,7 @@ PPP_TTY="$2"
 PPP_SPEED="$3"
 PPP_LOCAL="$4"
 PPP_REMOTE="$5"
-PPP_IPPARAM="$6"
+PPP_IPPARAM="$(echo $6 | sed 's/\./_/g')"
 PPP_UNIT="${PPP_IFACE##ppp}"
 
 export PPP_IFACE PPP_TTY PPP_SPEED PPP_LOCAL PPP_REMOTE PPP_IPPARAM