diff --git a/configs/extensions.conf.sample b/configs/extensions.conf.sample
index 1b09afc028f2cef170a558f50eb56f0af96d70d9..2489d183b9989de212f457bf63a4c83e6e27ae81 100644
--- a/configs/extensions.conf.sample
+++ b/configs/extensions.conf.sample
@@ -428,9 +428,9 @@ same => n,Set(isnresult=${ENUMLOOKUP(${EXTEN},sip,,1,freenum.org)})     ; perfor
 same => n,GotoIf($["${isnresult}" != ""]?from)
 same => n,Set(DIALSTATUS=CONGESTION)
 same => n,Goto(fn-CONGESTION,1)
-same => n(from),Set(SIPFROMUSER=${CALLERID(num)})
+same => n(from),Set(__SIPFROMUSER=${CALLERID(num)})
 same => n,GotoIf($["${GLOBAL(FREENUMDOMAIN)}" = ""]?dial)               ; check if we set the FREENUMDOMAIN global variable in [global]
-same => n,Set(SIPFROMDOMAIN=${GLOBAL(FREENUMDOMAIN)})                   ;    if we did set it, then we'll use it for our outbound dialing domain
+same => n,Set(__SIPFROMDOMAIN=${GLOBAL(FREENUMDOMAIN)})                 ;    if we did set it, then we'll use it for our outbound dialing domain
 same => n(dial),Dial(SIP/${isnresult},40)
 same => n,Goto(fn-${DIALSTATUS},1)