Testing CLAT for IPv6-only mobile networks

General
203

I just upgraded to 4.6 and this still looks broken
I thought some work had been done as just waiting for an OS update for us to have it?

204

Hi,

Sorry for the delay in answering.

Plain “broken” does not give enough information on what is happening.

Does the network offer CLAT?

Does the CLAT interface get up?

Does the CLAT interface output any traffic when using the device, like checking for IPv4 capability on some testing site?

Have you enabled logging according to, for example, this post?

Any other specific symptoms?

EDIT: Yes there was work done on making VPNs work well with CLAT.

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205

Hi, I have been busy (and I’ve bought myself a USB 5G dongle and another SIM card so I can use my laptop on-the-go).

Running version 5.0.0.62 - still not working

I don’t actually have much knowledge about what CLAT is

206

You could install ‘Device IP’ from openrepos and check if the clat interface shows up if you enable mobile data.

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207

Thanks for the hint!
It shows:

lo
127.0.0.1/8
------------------------
::1/128

rmnet_data0
172.xx.xx.xxx/30
------------------------
fe80::xxxx:xxxx:..../64

vpn0
10.xxx.x.x

Devive IP @ <time>

So for the rmnet, what I assume it’s the mobile connection, both IP4 and IP6 addresses displayed.

With VPN switched off, the vpn0 simply disappears and rest is equal.

With WLAN, I have the for lo the same as above, and

wlan0
MAC address
correct IP4 address
----------------------------
an IP6 address is visible

Device IP @ <time>

Does that mean I have CLAT working?

208

No, if you need clat, an interface called clat should show up with ip 192.0.0.1.

1 Like
209

How to install CLAT?
unfortunately:

Last login: Sat Jul  5 18:25:35 2025 from 192.168.0.25
,---
| Sailfish OS 4.5.0.25 (Struven ketju)
'---
[defaultuser@x10 ~]$ devel-su
Password: 
[root@x10 defaultuser]# pkcon install clat
Auflösen                                                                                                                                  [                                                                     ] (0%)  Paket nicht gefunden: clat
Paket nicht gefunden: clat
Ausführung des Befehls fehlgeschlagen: This tool could not find any available package.
[root@x10 defaultuser]#

CLAT also not to be found on Storeman and Chum.
and, is CLAT also available for old 32 bit Xperia 10?

210

If i am not mistaken, clat is a built in plugin of connman.

1 Like
211

Hi,

Yes, exactly as said in comment #210, CLAT is a built in feature. It does start only when
a) there is no IPv4 address set on your mobile data interface
b) ipv4only.arpa address can be resolved, which means that operator has enabled CLAT

and only when both conditions are ok, you will have a CLAT interface that will enable IPv4 connectivity through that interface, tunneled over your IPv6 connection.

Someone sent me logs about CLAT interface not coming up, and this was the case there as well, IPv4 address present → no CLAT. Even when the additional configuration, which is meant for development, is used to enable ResolvAlwaysSucceeds meaning that after IPv4 check has completed, the resolving of the aforementioned address succeeds despite the result of the resolving.

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212

CLAT has been added in 4.5, but got improvements in the recent updates. Just to keep in my mind, so you not suffer a fixed bug.

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