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Penrose, CO

Voip Concerns - Unblockable numbers, Second Opion Please!

Hello all,

I've got a whopper for you all, and require a second opinion.

I currently subscribe to Bresnan Triple play and my concern has to do with the phone service.. my EMTA is a ARRIS TM602G DOCSIS 2.0

As of late I've been getting a lot of SPIT (Spam over Internet Telephony) Mostly idiot robo calls or people who want people I have no clue about. They are annoying and harassing, and very hard to report to the FTC or the FCC for that matter. These people call at the most inconvenient times, and fill my voice mail box with half messages and half audible garbage..

Yes, I've been on the do not call list for over a year, both nationally and in my state.. I've had my telephone number for 15+ years and I don't care to change it.. I've removed my self and the phone number from the national marketing association, and other worthless attempts to enjoy a single dinner without some damn telemarketer or debt collector who thinks my name is Vernon.. (It's Gabriel...)

Some times these callers have fully formed ANI (telephone numbers) that I can put in our block list for a couple of weeks, and report, and that normally gives the jerks the hint..

More often than not, the headers simply say unknown with no telephone number, or worse a malformed telephone number.

Bresnan's current system allows these to pass. They are not blocked.. I'd really like them to be blocked.. Unless you have a phone number I can call back or report to the FTC, you don't need to call me..

I've called Bresnan and was told that they don't control *ANYTHING* regarding the ability to block these types of calls, and if they are getting past the anonymous call block that is already in place, they cannot (or WILL NOT) block them.

So, I called back, and asked if one could get the SIP authentication information, so that I could process the call & headers myself using asterisks or another VOIP solution. Even if I have to supply my own EMTA I'm okay with this..

I was told I could not, that was a violation of their terms of service, and that no SIP authentication information is generated..

I was told that my only option was to speak to the commercial side of the company.. and pay twice as much money for the same thing..

Well, I do know a little about SIP and I KNOW that my EMTA does talk with them via SIP over a separately provisioned channel in docsis. That they authenticate via a MAC, but there is still sip traffic I could listen to, and either handle the call myself, or hairpin the call, and drop the idiots before it actually rings my phone!

I technically can hair pin the call directly outside their modem, but based on the information I've researched , I'm not going to get any of the headers I could use to identify and report these idiots.

The splash page where I go to manage my phone is provided by NET2PHONE, and as far as I can tell, they provide SIP authentication!!!

I'd like to know what you think, and if you know of a better way to handle this situation.. HELP!



Bresnan's digital phone is not Internet Telephony. They're regular POTS lines that are carried over the cable modem and then converted to analog at the MTA. They don't cross through the Internet at all.
It's not SIP either, it's H.323 (they do offer a commercial SIP solution though).

As for the SPAM calls, legal action (or the threat of) is the most effective way to stop harassing phone calls. You can activate call blocking on your phone service and block the numbers if they call repeatedly.


Correction, they're running MGCP, not H.323.

»www.e-c-group.com/on-site-voip-e ··· pertise/

Powell, WY
reply to cablegeek01
More info: »www.metaswitch.com/download/Bres ··· snan.pdf


Penrose, CO

3 edits
reply to cablegeek01
said by cablegeek01:

As for the SPAM calls, legal action (or the threat of) is the most effective way to stop harassing phone calls. You can activate call blocking on your phone service and block the numbers if they call repeatedly.
@ CableGeek You cannot block malformed telephone numbers, nor can you block "Unknown" or "Private" numbers.

This is at the CORE of my issue.. When the Caller ID header is "NULL" or Malformed and or has less than ten digits, the system passes the call and will not allow you to block them!

Bresnan does not have the ability, or refuses, to provide the ability to block "Anonymous", "Private" or "Unknown" calls. (Including Caller ID headers that are Null or less than 10 digits)

* I know because I DO block the numbers I can, and I DO have anonymous call blocking turned on.. "Null" Headers still get thru!

Let me state.. I don't get calls from foreign countries, nor do I WANT *any* calls unless there is a number I can call back and raise hell on, or report to the FTC, FCC, or Local Law Enforcement..

Secondly, how do you harass a Automated Robo Call??

Thirdly, Asterisks can still act as a MGCP Gateway (Version 1.8)
I could still have the full headers from the call, process the P Assurance ID and or the other caller header information, and use it to report and drop these jerks.

Another Question, because my "Features" are controlled from net2phone, they are (thru Bresnan) still providing the DID right?

Finally, While I don't disagree that it could be MGCP, my conversations with the "Staff" there, was the reason I said it was SIP.. I will confirm this..

Again, do you have a better solution?

Children are our most precious resource
Helena, MT
reply to gjdunga
I am not sure but couldn't you write a script into your router that would block "malformed" numbers?
or maybe a script that sends all such calls to an endless loop of some elevator music?
Not sure at all and maybe just wishful thinking.
Team Discovery


Penrose, CO

3 edits
reply to gjdunga

That's the kicker.. as it stands right now, and is my complaint.
Bresnan told me flat out, that access to the network with my own equipment is a TOS violation. So apparently even if Asterisk can act as a gateway, they don't care, for security reasons. (I can see their argument, but I'm not convinced.)

Thus, the only header information I can obtain, is thru the EMTA's FSK burst.. (Caller ID)

In order to obtain that, I have to install a Hairpin device directly behind the EMTA.

That's an addtional device, drawing power, using more wires, and additional set-ups, and more delay, alas more to go wrong, to digitize a signal that was once digital, back into to digital and then turn it back to analog if it goes to one of my POTS phones.. on and on and on!!

That is unless apparently, I spend twice as much for service.. (Horse-hockey)

All of this is because they can't or WON'T filter malformed calls, and headers that are EMPTY or NULL when requested.. Apparently because they are afraid some one in a foreign country can't call you. I think they leave this loop hole open, to allow this kind of crap to go on!!

IF it was SIP, I could obtain the P-Asserted-Identity Header, P-Preferred-Identity Header, priv-value, etc... EVEN if the Network Asserted Header was anonymous, I could still gain valuable detail and information about the call..

In short, Caller ID does not send this kind of info, But SIP does!
INVITE sip:bob@billyjoebob.com SIP/2.0
Via: SIP/2.0/TCP useragent.cisco.com;branch=z9hG4bK-a111
To: <sip:bob@bilijobob.com>
From: "Anonymous" <sip:somespammer@q.com>;tag=9802748 Call-ID: 245780247857024504
Max-Forwards: 70
Privacy: id
P-Preferred-Identity: "SomeSpammerId" <sip:fluffy@q.com> 

ALL FSK will send is this...
04 12 30 39 33 30 31 32 32 34 36 30 39 35 35 35 31 32 31 32 51
04h= Calling number delivery information code (message type word) 12h= 18 decimal; Number of data words (date,time, and directory number words) ASCII 30,39= 09; September ASCII 33,30= 30; 30th day ASCII 31,32= 12; 12:00 PM ASCII 32,34= 24; 24 minutes (i.e., 12:24 PM) ASCII 36,30,39,35,35,35,31,32,31,32= (609) 555-1212; calling party's directory number 51h= Checksum Word

Anyway, I guess at this point all I'm doing is blowing off steam.. This still pisses me off big time..


Cheyenne, WY
reply to gjdunga
As cablegeek correctly pointed out, Bresnan "Digital Phone" is NOT "VOIP". There's a big difference between digital phone and voip. Personally, I recommend getting REAL VOIP. One of the best, and least expensive providers in the country is "VoipO.com". Check them out. Even if you lose part of your discount for NOT having a triple-play, you will only pay about 1/3 the cost for your phone. You'll also have a lot more control over it.

But if you want to try and keep bresnan phone and fix your problem, it is possible. Treat the OUTPUT (Analog signal from the bresnan phone box) that you normally connect your phone to, as an FXO line. Think of it as a C.O. line. Make this your TRUNK line to your PBX (Asterisk Server). Then, you can do whatever you want in the Asterisk. Bresnan has no control over what you do with the analog portion of the signal once you have it. Yes, this is double conversion. Yes, a slight delay. But unless you are willing to get "REAL VOIP", which bresnan is NOT, this is where you have to start. Once in your asterisk, you "might" have a chance of filtering certain calls. Best of luck.


Penrose, CO
reply to gjdunga

I agree with exactly what you have said. I can and do treat the output of the MTA as a CO trunk. I've been using this as a solution in part since koolkid responded. I have been looking at VOIP providers that don't suppress the privacy headers or the other "Identity" information. Do you know if that service provides unlocked privacy headers?

The information I got from a Bresnan agent before, wasn't completely clear, and as far as I know, it is MGCP not VOIP. However, Asterisk 1.8 will have full MGCP support, so the point as far as I can see, is mute.

What I have a problem with, and the reason I'm venting and griping here, is the fact that Bresnan refuses to restrict calls that have malformed headers.. I pay for a service, and they don't deliver.

My Goal is not to have to run a PBX!!! I pay for a service, and I'm having to Rube Goldberg a solution, that they advertise!!

Again by this definition I'm referring that the Telephone number is not a full 10 digit number, does not have the required CID (ANI) info, and it's also annoying that the toll numbers, that have suppressed their identity as well..

Now I know that there are reasons why companies like Bresnan, would allow this, as some international and satellite calls don't provide a full SS7 route or ANI / DNIS info. (If I understand the reasoning).. However As far as I'm concerned they are full of crap, and let me explain why.

Any international or satellite route, goes thru a domestic trunking station somewhere *domestically*.. A SS7 channel *IS* generated from that point on.. a code of "International Call" and a 0xxxxxxxxx Designator could be applied with the simplest of ease..

I live in, and Bresnan provides services in the "USA". Where I live there is Enhanced 911. This means by tariff, they have to provide to law enforcement or other emergency services the number, and address of any subscriber on their network. The same is true with 98% of the United States.

This means they have information to provide to a SS7 channel "Identity". Granted, users of such a service have the ability to bock their information, but the headers on such a call are part of the tariff. "Unknown" is different than "Private/Restricted".

This is "supposed" to be part of a Tariff, and Call-blocking is supposed to prevent numbers that are blocked from ringing thru..

I wonder if they do this because they get kickbacks from these advertising companies. Or perhaps they are truly incompetent blobs of flotsam, who can't manage a telco network.

Either way, it's freaking annoying and disgusting at the same time.. I see no common sense reason why Bresnan allows this, or allows malformed headers..

I forgot this.. If the call is originated from a VOIP provider over IP, to a SS7 gateway, the session information is still retained, even if the SIP headers are forged, the Orig IP is still part of the headers..

Sorry I've rambled.. I'm still pissed..


Cheyenne, WY

2 edits
reply to gjdunga
Go to »www.voipo.com and send them an email. I helped develop that voip company and think very highly of them. I use them, and since going live, I've backed out of the business side of the company. But they are probably one of the best companies available. If you email them, and refer to their engineering department, they should be able to answer all your questions about if their service can do what you want it to do. If you'd like to go to their forum and ask the owner/CEO directly; his name is "Tim", aka "VoipOTim" go to:
»forums.voipo.com/. You can mention that we chatted and I recommended you speak with him. They know me by christcorp and by Mike. Now that they are up and running 100%, they have a full engineering and tech staff that can answer all your questions. This provider was built on 2 years of alpha/beta testing. The entire service is based on what the customers wanted and not what the company wanted to provide. I definitely think you should check them out.

Also, Tim is on THIS forum in the VOIP section. You can ask him a question there also. Mike....


reply to gjdunga
On our Comcast CDV line;

Anonymous Call Rejection only works with Private callers with the privacy flag intact. That means no null/Out of Area.

Even then, the recording they play has no sit tones, so that automated dialers don't stop trying to call and make repeated missed calls in incoming list.

Otherwise they let through all sorts of bullshit numbers like (567) 000-5693 eg an exchange starting with a 0 or 1 is never assigned. (411) 693-4255 etc.

Call blocking or Forwarding selective only has room for 12 numbers. It will not accept the bullshit numbers, and no wildcards.

Even then, the recording they play has no sit tones, so that automated dialers don't stop trying to call and make repeated missed calls in incoming list. I have played with forwarding them instead of blocking and sent the calls to a disconnected number that have sit tones.

I now use Phone Tray on this line. The trick is to use a recording with sit tones so that automated dialers will stop calling. The actual voice part of the recording is only for the occasional human that may be listening to the audio. For Private, Out of Area, and 0000000000, my recording says I don't accept blocked or unavailable callerid, please unblock your callerid and call back. A legit human caller will hear that, while robo dialers just hang up right after the sit tones. All other blocked callers get a standard disconnect message.


Monrovia, MD

1 edit
reply to gjdunga