blocking scam calls

[#1]

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@paul_blitz wrote:

Do you ever get false positives? Or does your 'whitelist' generally stop that?

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Not that I know of. My familiy used to moan a lot when CLID didn't work, as they had to go through the screening process.

[#2]

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@Townman wrote:
All calls carry an originating CLI which might not be the Dane as the display (presented) CLI. These ought to raise alarm bells.

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Many genuine companies set up their systems so that any call presents the main switchboard number rather than the direct dial the call is made from, so that would create issues.

[#3]

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@orrery wrote: Many genuine companies set up their systems so that any call presents the main switchboard number rather than the direct dial the call is made from, so that would create issues.

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No issues at all.  The requirement is that the presented (displayed) CLI be a valid dialable number.  The presented CLI and the calling CLI being different should be a trigger for double checking that the presented CLI is a valid dialable number.

Given that this is an Ofcom requirement ... it is clearly not seen as an issue in the described circumstances.

See Statement: Guidelines for Calling Line Identification Facilities - Ofcom

"...we introduced a new General Condition (GC) C6 which requires Communications Providers (CPs) to provide CLI facilities, and ensure that the CLI Data provided with a call includes a valid, dialable telephone number which uniquely identifies the caller"

The detail in the referenced PDF is very interesting too...

• C6.2 Regulated Providers must provide Calling Line Identification Facilities, and enable them by default, unless they can demonstrate that it is not technically feasible or economically viable to do so.
• C6.3 Regulated Providers must inform Subscribers if Calling Line Identification Facilities are not available on the service they are providing to those Subscribers.
• C6.4 When providing Calling Line Identification Facilities, Regulated Providers must:
  • (a) ensure, so far as technically feasible, that any CLI Data provided with and/or associated with a call includes a valid, dialable Telephone Number which uniquely identifies the caller; and
  • (b) respect the privacy choices of End-Users.
• C6.5 Regulated Providers must not charge Subscribers any additional or separate fee for access to or use of standard Calling Line Identification Facilities.
• C6.6 Where technically feasible, Regulated Providers must:
  • (a) take all reasonable steps to identify calls in relation to which invalid or non-dialable CLI Data is provided; and
  • (b) prevent those calls from being connected to the called party, where such calls are identified.

It is quite evident that many CPs are failing to comply with GC C6 in full which has been a requirement since October 2018.

[#4]

This may be relevant - as of last week OFCOM say "Phone providers must now all block calls from abroad which imitate UK landline numbers, under strengthened industry guidance". ie no number spoofing to look like a UK landline or mobile.

Perhaps Plusnet could confirm they have implemented the block?

[#5]

Hi @Stoker thank you for getting in touch with us and for flagging this. 

I've requested some more information from management in regards to what measures are being put in place to reflect the new guidance from Ofcom, and as soon as I have more details I will be updating this topic. 

[#6]

@Tina11192  the OFCOM document says

BT reported it was able to prevent up to one million calls per day from entering its network within the first month of voluntarily implementing these measures. Ofcom’s new guidance will ensure this becomes standard practice across the industry.

Given that the phone service is provided by Openreach I would 'guess' that the BT in that above probably really means Openreach ? If that's the case then it would appear that it MAY already be implemented.

[#7]

@MisterW Fair point, I would presume so as well, however, it would be useful to know for sure on our end so that we can provide the support or reassurance required by the situation. 

[#8]

It certainly is a good thing, but just to correct your message, it does not include mobile numbers.

Phone companies must now identify and block all calls from abroad which falsely display a UK landline telephone number as a ‘Presentation Number’

[#9]

This is an interesting development, but I fear to some extent will be deeply problematic.

Many organisations have overseas customer service / support centres.  In principle where they call up / back a UK customer, I see no issue with them presenting a UK CLI which might indeed be the UK number customers call when needing to make contact.  It would seem that this new (knee-jerk) Ofcom "solution" might create more issues than it fixes.

All that is really required is full compliance with the GC C6 requirements which have been around since 2018 - that is the presented CLI must be valid and dialable.

This new development could become nothing more than business crippling red tape ... which if BT had complied with Ofcom's rules 7 years ago ... would not now be required.  As ever too little too late.

[#10]

I see no issue with them presenting a UK CLI which might indeed be the UK number customers call when needing to make contact.  It would seem that this new (knee-jerk) Ofcom "solution" might create more issues than it fixes.

There should still be no problem for 'legitimate' overseas callers. The requirement is :-

Phone companies must now identify and block all calls from abroad which falsely display a UK landline telephone number as a ‘Presentation Number’

AIUI They can still legitimately 'own' a UK network number even when abroad and as long as the Presentation number agrees with that then they will be ok.

[#11]

@Townman  -

Surely overseas customer service, etc, would be using VoIP, and wouldn't be making PSTN calls at international calling rates ?.

International VoIP over a VPN with a gateway in the UK, both the Caller ID and source IP address would be within the UK.

The above setup could easily be reproduced by a SCAM call centre, making Ofcom's "solution" useless.

.

[#12]

@outcast 

GC C6 requires that verification measures are implemented at network boundaries.  Thereby it ought to matter not how the calls are carried.  When they come into a specific CP's network the requirement is to not deliver calls having an un-dialable CLI.

@MisterW 

I read the requirement as being that no overseas originated call may present a UK CLI, be that valid or not.  Have I misunderstood?

[#13]

@Townman #

I read the requirement as being that no overseas originated call may present a UK CLI, be that valid or not.  Have I misunderstood?

I think so, although I dont completely understand the technicalities of 'Network number' and CLI (Presentation number). The requirement is not to falsely display a UK CLI. As long as the CLI has been allocated to the originating organisation then it should be ok, its not a false CLI.

[#14]

Surely the phone service is provided by BT directly? OpenReach are just the wires, aren't they?

[#15]

What do you mean by "BT"?

At one level, "BT" is "BT Retail" who sell telephone services to end users, but "BT Group" covers all of the different divisions for providing all of the various services for BT Retail and all of the other CPs and ISPs using that infrastructure.

Yes BT Openreach provides the wires; BT Wholesale sell the services to the retailers.  Services management between exchanges (etc) is provided by another bit of "BT".

But we are not talking about just "BT" here: any communication provider having a call carrying network must apply the same call management rules.  Sky and Talk Talk have carried their calls on their own (non-BT) network for a good while.