TIPS Stop Robocalls with iPBX

[bigjess007]

Hi everyone! I need some help and I'm hoping I'm in the right place.

My parents are constantly getting robocalls. They are older and shouldn't be chasing the phone and it's upsetting to them. I need to find a way to stop it. The have a POTS line and it has to stay, I can't do any external voip services. It has to be reliable as they aren't close but not too far away (not easy for me to just drive over). And it has to work, they aren't going to troubleshoot. I also have to worry about power outages (they're rural).

So will all those caveats I started searching around and found this guide (https://www.wrbishop.com/telecom/end-robocaller-solicitation-and-hangup-calls-with-asterisk/). BTW - I think at the end of all of this, it may be an excellent guide for a nerdvittles post as I can't think there aren't more folks who would want to do this, and I couldn't find any specifics to stopping robocalls via this method.

It covers the general idea of what I want to do but not routing the calls exactly like I want to. I was planning on following this guide (http://nerdvittles.com/?p=10151) for initial setup and then configuring for the OBI from the other guide and then all of my routing rules. I hate to have to buy the latest RasPi, an older one will do but it seems they are hard to find and if this catches on I want to make it easy for anyone to follow a guide with current stuff.

I need to be able to remote manage this solution, which I believe I can do. I have a router installed at their home, and I remote desktop in to their computer all the time. So the PBX will be protected from the outside by the router, and if my understanding is correct I can get to the PBX from their computer via web interface.

I do have one major issue though and that is in the event of a power outage. From what I've found here (http://www.obitalk.com/forum/index.php?topic=2872.0), the newer OBI110's don't have the relay that bridges the FXS to FHO port in the event of a power outage. So I'm going to have to look at adding an external relay. I'm not happy about it, but so far this is the only solution I've found that will do everything I want and at a cost effective solution (if you call over $100 as a one time cost a solution to stopping this harassment).

So with all that said I'm looking to move forward. I'd first like to ask everyone's thoughts. Is there a better solution? Better hardware? Remember please that external voip isn't a solution, their phone number / POTS line can't change. It needs to be rock solid and remotely manageable.

I've been trying to read all the asterisk guides and learn about this in regards to the dial plan and I think I need an expert's opinion.

Here's the call flow I envision.

I'm going to have both a whitelist and blacklist database. And I want to filter by BOTH the caller id name AND number fields with wildcards (this seems tricky).

So if a call comes in that matches name or number on the whitelist, I want it to ring the phone, the caller shouldn't hear music or have any prompt, they shouldn't even know it went through the PBX. I want that call to ring until the caller hangs up.

If the call matches any name or number on the blacklist, I want the PBX to answer, and play a disconnected message with the SIT disconnected tones at the beginning and then hangup. (there seems to be alot of argument on whether this is a good strategy or not with robocalls, I want the call answered so I can hangup on them instead of letting them ring forever and tying up the line. So since I'm going to answer the computer is going to know the call is answered, I figure I might as well try to discourage them with the SIT disconnected tones). The home phone should not ring, no callerid should be passed, my parents should not have any idea the PBX bounced a call.

If the call doesn't match name/number/wildcard on either list, I want the following to happen: PBX answer's the call, play a recording that says this number does not accept any solicitation or courtesy calls of any kind, all calls to this number will be recorded and by continuing you consent to said recording and to continue please press the key on your keypad that is the answer to the math problem 3-2. (Maybe a little jerkish, but no more than the 10+ calls a day to folks who don't get around so well.) If the caller presses 1, ring the home phone until the call hangs up. If the caller doesn't press 1, then it is hanged up. I'd also like to see if in the callerid logging there would be a way to note the callerid information of callers who called, got challenged, and didn't accept the challenge (so I could add them to the blacklist).

I want all inbound callerid's logged as well (I want to see how many calls they continue to get, see if this decreases).

Managing the PBX needs to be able to be done via a computer on their network (via remote desktop), I want to be able to see the callerid log and adjust the black/white lists as well.

I know this is one long winded post so if you're read this far a big thanks!
Thoughts, comments, suggestions?

 

[MacNix]

have you met Lenny?

sip:lennySip.itslenny.com:5060

that is all.. you're welcome.

 

[bigjess007]

Ya, I've seen Lenny in my googling. Also the screaming monkeys. If I wan't afraid that it might end up making more calls for my parents I thought about having the system answer those cardholder and life alert calls, hit "1" for more information and then when it heard someone on the other line play a sound file that would be so loud it would hurt the ears of the person on the other end. Evil maybe? Can't be any worse than what they are doing to my parents.

That being said, back on topic. Help!

 

[MacNix]

Seems to me it'd work.

Neither way is very fool-proof: you're creating a pretty complex stack of stuff between the telephone and the CO line.

IF you are worried more about Mom & Dad having a fool-proof way of calling out in the event of a power loss, I'd probably do the following:

1. a small UPS (considering the Raspii uses about 8w and that MAX an OBI could possibly draw is 12w) would power the two for days,​

and​

2. put a phone splitter pre-OBI, get a VERY CHEAP ole POTs phone, turn the ringer off, and have it just sitting there..​

Then, in case of a power outage, they're still up & operational for some time in the event of a power loss..

It might also be handy to put a CCFL 15w lightbulb lamp on it, just so they can see to get around if it's dark (that would still have you drawing less than 50w total - about 20hrs running all at full power, or about 60hrs running the phone setup only at idle).

And then even if the power goes out AND the UPS goes dead, they STILL have a working phone, without having to plug a single wire....


This highlights some of the issues with any of these additions/changes to the POTS mantra, which has (for a century) focussed on one thing, and one thing only: reliability.

In another life, I had a friend in the phone industry. His job was to maintain switch stations around north FL.. I think he managed about 10 or so, don't remember.. I do remember his explanation of the depth of redundancy though - EVERY system they had was developed to the 4th layer of redundancy.

We in modern computer worlds rarely go beyond a single layer of redundancy: we have ONE data backup, we might have a UPS that'll get us a few minutes or an hour of run-time, and then we're down.

These guys made careers out of making sure that the phone system worked so well you could stake your life on it.. and many people have...

That's one of the components that really makes me hesitate about not having a POTS line in my house sometimes....


all that said, if it were me, I'd still failover calls to lenny...

 

[bigjess007]

I've been thinking about the redundancy alot. I thought about a UPS but that's adding more $$ to the equation plus it's a finite amount of power and more to possibly go wrong. They already have a wired phone in the kitchen and after reviewing that obitalk post about the missing relay in the obi110, I've decided that the 120v relay route that's described later on in that thread is the safest way. I'm going to put the kitchen phone on the relay. They already have to use the kitchen phone in the event of a power outage because they have a multi-cordless handset system that stops working in a power outage. So that 120v relay solves all the issues there and I think it's the safest as it will "fail safe". This way also let's that phone keep the ringer turned on so in the event of a power outage someone can still call and they will hear the call. Plus I was thinking one added benefit of this method is I'm going to have the raspi and obi110 on a power strip and if for some reason everything goes stupid and they can't make/receive calls I'm going to show my dad how to flip the power strip off and again everything "fails safe" to the kitchen phone until I can get out to fix things. I know I have to do some testing in regards to yanking the power and ensure that when power is restored the raspi and obi110 come right back up and start working again (I've come across info that says db's can be corrupted in the event of a hard shut down, so that's another thing on the checklist).

And in regards to Lenny, he's funny, but in reality the callers won't stay on the line long enough (99% of the calls are robocalls, not live calls) so I just want to get the call dealt with and move on. Like I said I've thought about having the system press 1 which seems to be the standard response to get a live agent on the line and then play the loudest sound I can to blow out their eardrums, but in reality it won't stop em.

 

[bigjess007]

I don't think dead air will discourage these calls because I've answered the line and muted it immediately so no sound was transmitted, and the message just played over and over until I hung up. So that's why I want to answer the call, play the SIT disconnected tones, and then hangup on blacklisted calls to get rid of them as fast as possible. If you don't answer the call it will just ring and ring and ring, so it's tying up the line that way thus my reasoning for needing to answer them to hang up. Answering them confirms to the dialer program that they got a bite, but hopefully playing the SIT disconnected tones discourages them. If it doesn't so be it but this seems to be the fastest way to get rid of them.

I think the blacklist module playing a SIT disconnected tones and associated message audio file will do what I want. I'll be managing it by GUI so no need for the DTFM method.

The whitelist module definitely seems more complicated but again doable. BTW, don't both the blacklist and whitelist need a db?

So not being able to black/white list by CNAM doesn't make me happy, but it is what it is, pretty sure my call flow will still catch everything I want. The reason for this is yes, there are two instances of robocalls where these scammers use the same exact CNAM but changed the CID. They are slick little b@$t@rds. They'll use the same cnam, and the first 7 digits of the cid stay the same, only the last 4 change. "Rachel from cardholder services" and "lifealert" both do this, guessing they are also trying to stay ahead of being blocked. So I planned on adding the CNAM for these calls to the blacklist and then catch that name instead of the number. It's not a deal breaker by any means, was just hoping to catch and quickly discard as many of these garbage calls as possible. Since I can't catch them it's more calls that have to go through the challenge phase and tying up the line more than the blacklist path but it still will stop the phone from ringing.

Is it going to be easy for me to see in the logs the calls that got challenged but didn't pass the challenge? Possible to highlight this? Most likely those failing challenge will be more roboscammers that need the CID added to the blacklist to get rid of them as fast as possible.

I've also seen the suggestions to blacklist exchanges but unfortunately I can't do that either, the calls spoof a local number.

 

[ostridge]

Sometimes they spoof a local number say 7 digits only, so you could match the short numbers (if without area code) and send them somewhere else perhaps even their own toll free number, else ring forever (300).