Accept SIP REGISTER from home and from known usernames

-A SIPREGISTER -s 83.162.196.192 -j ACCEPT
-A SIPREGISTER -m string --algo bm --string toestel_ax112 -j ACCEPT
-A SIPREGISTER -m string --algo bm --string toestel_sipura -j ACCEPT
-A SIPREGISTER -m string --algo bm --string toestel_nessy -j ACCEPT
-A SIPREGISTER -m string --algo bm --string toestel_neo -j ACCEPT
-A SIPREGISTER -m string --algo bm --string "budgetphone.nl" -j ACCEPT
-A SIPREGISTER -j DROP

accept SIP INVITE for some numbers

-A SIPINVITE -m string --algo bm --from 30 --to 49 --string "sip:xs4all_70907_in@" -j ACCEPT
-A SIPINVITE -m u32 ! --u32 "34 = 0x20736970" -m comment --comment "\"sip:\" at byte 34" -j DROP 
-A SIPINVITE -m u32 --u32 "37&0x000000FF = 0x30" -m comment --comment "2nd digit is 0" -j DROP
-A SIPINVITE -m u32 --u32 "37&0x000000FF = 0x40" -m comment --comment "number is one digit" -j ACCEPT
-A SIPINVITE -m u32 ! --u32 "36&0x000000FF = 0x30" -m comment --comment "first digit is zero" -j DROP
-A SIPINVITE -m u32 --u32 "46&0x000000FF = 0x40" -m comment --comment "call to 10digit number" -j ACCEPT
-A SIPINVITE -j DROP

stuur VOIP verkeer naar juiste chain

-A VOIP -m string --algo bm --from 23 --to 28 --string "INVITE " -j SIPINVITE
-A VOIP -m string --algo bm --from 23 --to 30 --string "REGISTER " -j SIPREGISTER