I want to block calls from a particular number on all trunks. I added the number to the blacklist and all works well on SIP trunks (except that the caller gets number unobtainable tone rather than an announcement). I have a DAHDI trunk which seems to behave in a weird way. The calls all come on that trunk so I really want it to work.
If the number is in the blacklist the call comes through normally but the caller ID is shown as UNKNOWN/UNKNOWN on the phones and is not blocked. I initially thought that the DAHDI trunk was not getting the caller ID properly but I have done a fair amount of testing and it works properly on other numbers. Taking the number out of the blacklist caused the caller ID to work properly again.
Are there some other tests I can do to find out what’s going on? Is there a way I do the same thing instead of using the blacklist module?
I’m in the UK if that makes any difference.