Unable to raise SIP ALG/MAP-T Issues

[Infneon]

Hi,

My backround is IT, I work with VoiP and networking everyday.

Currently having an issue getting my work VoiP phone to pass voice traffic. We have FTTP Gigabit using the SR213 and it's woefull admin panel.

When using the form linked elsewhere to raise a VPN issue (its not a VPN issue but others have had success asking for SIP ALG and MAP-T to be turned off by using it) they are unable to link my mySky login to my account, even though the broadband services are there. This is also backed up by the fact that if I try to use the broadband checker tool, it says there is a probem with my account. I've tried to walk through this with telephone support but they were recommending redownloading the app, using a different browser etc. I've tried this through Chrome and Firefox to rule out a Web engine issue and on an iPhone and Android phone to rule out an app issue. I've recieved a text last night saying the issue is fixed, its not.

The real issue that I need to get fixed though is that I have a SIP VoiP phone that connects back to an 3CX server located at my office. After the update the router recieved on the night of 5/12/24 this no longer works. The phone will register but will not pass the packets used for actual calls.. Looking at Wireshark, on both home and work networks, the packets are not getting passed the Sky SR213. I've also tried to raise this via phone support but I was told they don't have any idea what I am talking about.

Self troubleshooting wise, if I run the phone through a different connection, everything works fine. I have confirmed this using a phone hotspot and a non sky connection. I have also used a different model handset to rule out feature depreciation.

I need to escalate this issue as 1st line support via phone calls are unable to understand the issue to actually resolve.

Thanks

[Lisa-P1987]

Hi there, I’ve escalated your post to our Community Messaging team who will invite you to a private chat shortly and help you with this. 

Just look out for the colourful bubble to start the conversation.

Here's more information on how Community Messaging works - https://helpforum.sky.com/t5/Did-you-know/Escalating-a-post-to-a-Sky-expert/ba-p/3711147

[Suella]

Why have you cancelled my sky engineer for today need it rebooked ASAP 

[Chrisee]

@Suella you are not addressing Sky by posting a question in a random forum thread on a different topic as this is a customer to customer channel.

The usual reason why engineering visits are cancelled is because Openreach have looked at the job and do not consider it is now necessary. To find out details for your casecall Sky and ask

[-rpnz-]

Hi @Infneon 

Do you know if you're using encrypted SIP with large certificates that may result in fragmentation?   Would you be OK with sending us the pcaps from Wireshark so we can confirm if it's the same fragmentation-related issue that's impacting VPNs, or something more SIP related like an ALG function?

If you haven't already, you could also try enabling UPnP or Port Forwarding to be removed from IPv4 address sharing, which may help with SIP/ALG-related issues.   But if that still doesn't work, see this thread here on how to request that MAP-T be disabled.

[bradleythedog]

HI@Infneon 

I too am having the same issue here.  I am using a BT Wholesale based SIP phone and the problem started last week.  i've tried going through the Virtual assistant but that is a waste of time.  My telephone provider has been round and has hit the same issues as you, he did suggest swapping routers, but he says that because of MAP-T, this isn't going to work.

Have you managed to get any further and if so could you share?  Not sure of any other way of getting Sky to deal with this.  my wrk is suffering because of this.

[TimmyBGood]

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@bradleythedog wrote:

HI@Infneon 

My telephone provider has been round and has hit the same issues as you, he did suggest swapping routers, but he says that because of MAP-T, this isn't going to work.

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My understanding was Map-T is specific to the Sky Max Hub being in use.

[Chrisee]

@Infneon to explain a little more MAP-T is only used if the router says it supports DHCPv6 Option 95 which the white Sky hub does but most others don't except for Ubquiti models which gave the worst of all worlds in that they said it was supported when in fact it wasn't. Thst is in the process of being fixed at long last by Ubquiti.Asus routers seem unaffected and connect quite easily.

You mention your service is from BT Wholesale i hope you are aware that Sky do not use BT Wholesale at most exchanges as they have their own backhaul?

[bradleythedog]

To confirm, the VoIP phone is hosted by BT Wholesale, I'm not getting confused with exchanges, it doenst matter what internet connection we use.

FYI the router I have is SR213, I presume that is the Sky Max hub?

[Lisa-P1987]

Thanks for escalating this. We’ve sent bradleythedog  an invite to chat.

[Infneon]

Wife (named account holder) and myself spent a good 2 hours with the accounts team yesterday and they were able to match up the services with our mySky login. I then used the form again at https://www.sky.com/help/forms/vpn-configuration asking for MAP-T to be disabled, about an hour later my connection dropped and then my phone lit up registered and passing traffic.

https://www.sky.com/help/forms/vpn-configuration really needs to be updated to say its not just for VPN traffic but any issues relating to MAP-T and IP sharing.

[TimmyBGood]

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@Infneon wrote:

https://www.sky.com/help/forms/vpn-configuration really needs to be updated to say its not just for VPN traffic but any issues relating to MAP-T and IP sharing.

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Excellent result ; )

I've raised the point you mention with Sky previously, and I'll do so again.  While business VoIP phone hardware is rather rarer for WFH than software VPNs, it's definitely out there and being affected by Map-T.

[TimmyBGood]

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@bradleythedog wrote:

FYI the router I have is SR213, I presume that is the Sky Max hub?

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Yes it is.

[-rpnz- · Accepted solution]

Glad to hear your SIP issue has been resolved.

So this seems to be a new bug recently introduced with the SIP ALG function in combination with MAP-T, although not directly an issue with MAP-T itself.   The good news is that it will be fixed in due course, along with the fragmentation issue impacting VPNs; disabling MAP-T will not be a long-term solution.

[RhysCozens]

Hi

I have also ran into recent issues using a VoIP softphone via my home network.

I come from an IT background too and have tried all sorts to get this working.

I presume it's a new bug on Sky's part as this has worked fine for many years, and Sky insist that no settings have been changed and all restrictions on my router are disabled.

I have tried other networks, including a mobile HotSpot which all work, although this is not sustainable and the issue must be addressed.

When will this be fixed please, and what else can you suggest to try? Articles have suggested disabling SIP-ALG but I can't find a setting for that anywhere.

PLEASE HELP!!