Registration fails when Internet goes down and back online

I have a Gigaset N300a IP that is connected to the Linksys Hydra Pro 6 router. I have been having issues for couple of months now where I get registration failed. I was trying to fix it, it seems to apparently be routing but still don't know how to fix it. So I changed on the Gigaset interface the ip address assignment to static with preference dns 8.8.8.8 and alternate dns is empty. That seems to fix the problem slightly with on the router reserved the ip address. So then this has helped me from stopping turning the mains off for router and gigaset. Since just rebooting it or turning mains off for gigaset didn't work.

However the problem is still there so I have partially fixed now I just need to reboot gigaset from.interface or just turn it off from mains and fixes it. But still get the problem if Internet goes down and back online the registration failed then have to reboot the gigaset which I don't want to keep doing. Also I have done port triggering which is also not helping. Is there a permanent fix to this, I don't know how how to fix it.

Can someone help me please. I don't know what to do. Really miss the copper line for landline so simple. Also I saw this option called STUN when entering the credentials voip and setting it up on advanced setting. Would STUN help or not don't really know what it is. Or is it something on the router I need to change don't know what to do.

SOMEONE HELP ME PLEASE

Edited by HAli24 (Thu 21-Dec-23 05:51:37)

From a position of very little experience, I would be looking at these things:

* Is your internet connection set to be fully online all the time or does it have some level of connecting on demand
* who provides your internet and your voip
* can you use a wire ethernet voip phone on the unit, if so with what result?
* what is the registration timeout on the unit and what happens if you wait at least that long after discovering the problem
* can you ping the registration site when all is working OK and if so, can you then ping this site when the unit has gone down

Edited by DFScale (Thu 21-Dec-23 09:19:48)

I can't find anything device specific for the Linksys Hydra Pro 6. Does it have an option for SIP ALG? Possibly under Configuration > Administration > Gateway Function. If so, I'd start by ensuring SIP ALG is disabled/turned off. It's been a few years since I've played with SIP, but I vividly recall that 90% of my issues were due to SIP ALG. Even on relatively expensive Fortigate firewalls.

Yes it does and it's turned off from the start.

On router Internet connection type is keep alive redial period 30 seconds.
The provider is for both is one company called Octaplus which provide Internet and voip.
I am already using ethernet the gigaset is connected to router through cat5e ethernet cable.
I know Registration refresh time is 180 sec
I don't know what you fully mean with registration timeout is it on unit interface.
I know that originally takes 7 days then registration failed.
I know that if I leave it alone with registration failed even up to 24 hours it still registration failed
I can ping it when it's working and not working do through router interface right.

What indicates that the Registration is lost? If the Gigaset indicates a loss of registration, it should try again (at certain intervals until it succeeds).

When your broadband goes down and comes back up again, does the public IP address change (my guess is that it does). Then the Gigaset would need to register again as otherwise the VoIP server would not know your new IP address. Keepalives won't help, because they only keep the NAT rules in place.

I looked at the Octaplus website, it seems they offer FTTP only. Are you on FTTP, i.e. the Linksys plus into the ONT?
Why does the broadband go down from time to time if it really is FTTP?

If you get broadband and phone service from one provider, you should raise the problem with them. Do they offer static IP addresses, could not find anything on their website

It indicates on the handset which is a dec phone so connected to gigaset N300A IP. Yes it seems public ip address does change. So on the router should I change it to 'connect on demmand' that is the other option instead of keep alive. I am on 900Mbps so yes I am FTTP. And it does landline option is Select landline option
Keep my current landline number
Get a new landline number
No Landline Required.

I donteven know why Internet goes it's pretty much gone bad with the maintenance and loss of Internet. So outages occasionally happen. Unfortunately today my Internet went down and then came back online and voip registration failed and then reboot the gigaset N300a IP then registration worked.

The router is connected to ONT I am using my own router since its good but problem just with voip. And the way its connected is through PPPoE. So because of this I don't have to use bridge mode. However had to buy a voip because of using my own router. I wonder if I I bought a voip adapter would I get same problem. But still just want to fix the gigaset N300A IP.

They do offer static ip address for ipv6 the problem is it occasionally drops now. And for 1 week they turned it off due to server maintenance. I have been trying but they always are busy. I feel its routing problem but don't know how to fix this.

Even if you see octaplus status page is crazy like amount of maintenance and fixes is crazy starting to regret getting full fibre and especially voip. It was so easy back in the day using copper cable for landline no problems.

In reply to a post by HAli24:

However had to buy a voip because of using my own router. I wonder if I I bought a voip adapter would I get same problem. But still just want to fix the gigaset N300A IP.

They do offer static ip address for ipv6 the problem is it occasionally drops now. And for 1 week they turned it off due to server maintenance. I have been trying but they always are busy. I feel its routing problem but don't know how to fix this.

Even if you see octaplus status page is crazy like amount of maintenance and fixes is crazy starting to regret getting full fibre and especially voip. It was so easy back in the day using copper cable for landline no problems.

Did Octaplus provide you with a router from them? Could you try that just to rule out YOUR router settings for a couple of days.

FTTP should never drop unless (a)set to dial on demand OR (b)some kind of fault on the connection.

Definitely keep trying Octaplus on the phone, as I think they should be able to provide better advice on why your connection is dropping. If it is indeed your FTTP connection dropping, and not just the Gigaset rebooting itself.

Is the Linksys router "New" to you - or did you use it on a previous ISP? Do you know its a stable platform in the first place?

The connection will still drop even if I use Octaplus router overall its kinda just bad company with so many times Internet goes down. So just fault with connection. They did give advice it was due maintenance so its their fault on their side unfortunately. It's a stable router.

Have a look at this article https://www.sandon.it/2022/11/13/voip-behind-nat/ it discusses issues similar to what you are experiencing.
Also check whether Octaplus use CGNAT, i.e. does your router get a public or private IP address from the ONT.

It get private IP address from ONT

AIUI VOIP equipment if problematic if you are behind CGNAT.

But as you have IPV6:

The Cisco SPA 191 supports IPV6.

This should connect to a VOIP provider such as A&A that supports IPV6. Connect the N300 to the phone port on the SPA 191,

They use CGNAT unfortunately would STUN help with the issue I am having

STUN enabled: Yes No
STUN server address:

STUN server port:
3478
STUN refresh time:
240
sec
NAT refresh time:
20
sec
Outbound proxy mode:

Whilst I don’t profess to understand the finer points of this thread (there are much more learned people on the scene) I wonder whether AAISP L2TP service might provide a possible solution to the apparent CGNAT issue.

They appear to offer a very modestly charged version (Light) specifically aimed at the VOIP/CGNAT problem.

See Here

Of course there is still the issue of establishing the outbound L2TP connection which depending on the OP experience (and availability of kit) may be an issue

So the OP is up against two instances of NAT, one in the router at home and another CGNAT at the provider. I have some doubt that you can get VoIP to work reliably in such a situation. So, the options are:

1) get a static IPv4 address from your broadband provider

2) check whether your router supports VPN termination and then set up a VPN (there are providers that offer free trials), ideally one with a static IPv4 address. (Note that you may not be able to watch BBC over the Internet any more if the VPN server hands out a non-UK IP address)

3) investigate IPv6: I don't know whether the Gugaset supports IPv6, but if it does, this may be the cheapest option.

Heavily snipped

In reply to a post by essex_man:

2) check whether your router supports VPN termination and then set up a VPN (there are providers that offer free trials), ideally one with a static IPv4 address. (Note that you may not be able to watch BBC over the Internet any more if the VPN server hands out a non-UK IP address)

At the risk of going a little off (immediate) topic, whilst it is a steep learning curve (and in my case not withstanding years of usage continues to be so) this aspect of multiple interface routing and utilising VPN’s was one of the reasons I went down the pfsense route.

Download here

Certainly not a quick fix, but as a longer term solution for the OP I would recommend it - just about anything is possible with pfsense.

As to the existing router, this presumably could be re provisioned as a WiFi access point connected to the local network, so no loss of WiFi functionality, albeit there would be the expense of additional hardware to host pfsense.

In reply to a post by essex_man:

So the OP is up against two instances of NAT, one in the router at home and another CGNAT at the provider. I have some doubt that you can get VoIP to work reliably in such a situation...

I've run exactly this configuration with Voipfone through a HT801 ATA for the last 18 months without any problems. The HT801 was pre-configured by Voipfone and it just works, so I don't claim any credit for this. But it can be done.

Mine did the same. Gave up on it in the end. I had to switch between dynamic and static ip to force it to go and re-register.

Got a Yealink now. It does the same thing but the internet has to be off for longer. It picks up some stupid IP address instead of the static one allocated by the router. I have now set that to manual as well. STUN seems to help with call quality issues but not this. I haven't tested it with manual everything yet as there's only just been an Internet outage long enough to trigger it.


I have concluded VOIP isn't very robust. I had vonage for years and that was flakey a lot too.

Only other thing I can think of is to find if there's a specific number of retries before it gives up trying to re-register and increase that number to a much larger amount so that smaller outages don't bother it.

If a reboot always fixes yours then the lazy answer is to probably have one of those wifi plugs on it and reboot it that way. The tapo ones I have seem to be pretty tolerant of internet going away and coming back.

In reply to a post by serichards:

I have concluded VOIP isn't very robust. I had vonage for years and that was flakey a lot too.

I tend to disagree, I have been using VoIP for outbound calls on an ADSL2 broadband connection for 10+ years. Saved me £££ over POTS priices, especially when calling abroad. Just over a year ago, I ditched the copper landline, moved the broadband to Three and my ex-BT phone number(for inbound calls) to A&A.

There have been some occasional problems with interoperability between the SIP client and server, but copper landlines go down as well (diggers damaging cables, ripped dropwires etc.) so all in all VoIP has been serving us well and saving a lot of money.

Having said that, I made sure only to sign up to broadband services that provide a public (non-NAT) IPv4 address and a VoIP client built into the router (so the VoIP client is aware of any change in the public IP address and re-registers automatically).

I am amazed to read that FTTP broadband connections frequently go down, seen that a lot on our ADSL2 connection but one would have thought that optical fibre was more reliable. Even my 4G connection on Three stays up 24/7 and keeps the public IPv4 address for weeks.

I have heard that if I change transport type to TCP it will help for CGNAT. So I did try that but instead just stuck with registration failed until changed it back to automatic which is very weird which made it work with automatic transport type. This is the link: https://knowledge.crazytel.com.au/en/knowledgebase/a...

But it didn't help at all so don't know what to do.

Anyone got a solution please don't know anything else to do. Should I just change voip equipment and get like a Yealink or something I don't know. Been trying to contact broadband provider but no luck probably after new year's

I used to use an N300 and had the same issue, but use an N510 IP PRO now.

I remember trying all sorts of settings - not sure if I did resolve it - but in Settings > Telephony > Connections > Automatic check for profile updates - I set this to NO

Not sure if this did anything as a while ago - and I know it doesn't sound directly related to SIP registration.

In reply to a post by HAli24:

I have heard that if I change transport type to TCP it will help for CGNAT.

The VoIP provider needs to support TCP as well for this to work

I have finally got static IP just hoping this solves the problem so far its seems good had an outage but was only for like 15 minutes. Won't know for sure until an actual outage pretty long or something like that.

I had the same issue with mine around 10 years ago and I was using Google DNS. Switched to another DNS and all ok.

Never had an issue after that. However n300 only supports ipv4 so you're stuck if behind CGNAT which Octaplus use. I have just recently moved to using a Fritz!box that Zen supplied as my SIP gateway ( I have a separate Asus router for the connection) the Fritz!box supports SIP over IPV6. I registered my existing handsets to the Fritz, almost seemless! This information might be useful to others behind CGNAT although you're paying for a static IPV4 so your problem should go away now.

Now got new problem. Started today the n300 showes its registered but I get no connection when calling sometimes and also it says phone is busy when calling someone. I restarted and seems fix problem but what is happening can anyone help.

Please let me know if you ever resolved your issues using the N300 over Octaplus.
Did Octaplus ever fix the dropouts, or help you in any other way?

Octaplus offer cheap broadband from City Fibre, but if they dont support VOIP I'll have to give it a miss.