Airtel is rolling out IPv6 on their wired broadband services

[rohitks]

on airtel so far i was getting double the speed on fast.com but now even if i have ipv4 & ipv6 the effective speed is same as my plan?
anyone getting the same observation now?

 

[dkdhanda8]

My upload speed seems to be lower at peak times like 2:1 ratio

 

[Chip]

It has finally happened. My connection or rather the area of the city that I live in was upgraded to IPv6 most likely yesterday after a downtime of about 6 hours during which I think they upgraded their backend equipment. My ONT, the Nokia 2425A, was automatically pushed the configuration and WAN settings now show IPv4/IPv6 instead of "IPv4" previously. Also, DHCPv4 assigns a public IPv4 address even today unlike others in some cities where Airtel has shifted to CGNAT. So I get both a public v4 and v6.

So once I had discovered this change I had to experiment. Everything works like a charm when connected to the ONT's wifi but pfSense obviously requires extra configuration. For pfSense, configuring WAN for DHCPv6 assigns a v6 address to the WAN connection. However I am unable to get it to delegate to the LAN port and of course other LAN devices. Some more trial and error is required.

Also, I found using a static IPv4 on pfSense disables IPv6. So basically you need to choose what you want. I am sticking with a static v4 for now. I am paying for it so may as well use it.

 

[ishanjain28]

@Chip Are they giving a /64 or a larger block? Is it possible to get a larger block than a /64?

Also, is the prefix static or dynamic? as in, do you get a different prefix if you stop the tunnel for 10 minutes and start it back up or do you get the same prefix again?

 

[Chip]

@ishanjain28 The Nokia ONT is configured with a /64. These v6 addresses will be dynamic as the default setting is DHCPv6-PD. I used the same settings on pfSense and it assigned a v4 and v6 to the WAN port.

 

[Chip]

Guys, do note, v6 does not work with static IPV4. You must have PPPoE v4 connection as that is used to request a v6 address. Checked it twice already and reverted to static. Of course I will experiment more in due course.

In a nutshell with Airtel you either have:
1) A paid static IPv4
or
2) A PPPoE dynamic public IPv4 (CGNAT in some places) + a dynamic IPv6.

It's your choice.

I am not sure how it is set up in your cities/States. If someone has a 3rd party router and has a static v4 please experiment and let me know. First please ascertain if v6 is rolled out in your area. Remember, in metros/Tier 1 cities they are rolling out in phases. It MAY be experimental so if v6 is shut off don't be disappointed because your connection is perfectly functional with a v4. 😀

 

---

[panks21]

@Chip I can confirm. Both of your points are correct. I have static IPv4 and IPv6 doesn't work with that
IPv6 works with PPPoE only
BTW please feel free to DM me in case you need help with IPv6 on PFSense. I have done it multiple times on both OPN and PF Sense on Airtel

 

[GR2]

@Chip Are they giving a /64 or a larger block? Is it possible to get a larger block than a /64?

No. I used to get /64 few months ago. Now i am getting/128

 

[ishanjain28]

These v6 addresses will be dynamic as the default setting is DHCPv6-PD

This is irrelevant. They can still give you the same prefix every time.

 

[ishanjain28]

@GR2 Ridiculous. How are they expecting anything to work with a deployment like this. :/

Has anyone here tried requesting a larger prefix using dhcpv6? Does that work? (Set prefix hint to 60 or larger and then check if it got a larger prefix?)

 

[Chip]

@ishanjain28 I am not sure if the prefix remains constant or not, haven't experimented enough and frankly couldn't care too much as I am on a static IPv4. But the Nokia ONT has a /64 PD value which means the first 64 bits are probably constant and will work per their DHCP server configuration. I will need to check if it accepts a /60 or higher but I doubt it.

So I used the same /64 PD value on pfSense and it worked pretty well till I realised it did not assign a v6 to devices on the LAN. Obviously that requires more tinkering which I may resort to in due course with some tips from @panks21

Thanks @panks21! Can you share a screen shot or just a small post with your Airtel v6 WAN settings and that of any changes to LAN, track interface for example, and pfSense RA. I have v6 configured properly for Tata Play and those settings remain permanent. Not sure how Airtel differs.

 

[Chip]

Guys, this is the Airtel Nokia ONT IPv6 PD value (/64).

 

[doineedto]

Same here! Getting a /64 address on the Nokia ONT, but a /128 address on the bridged router. Previously used to get a /64 address on the bridged router as well.
Effectively, none of the downstream devices can use IPv6.

 

[Chip]

@doineedto I am able to get a v6 via the Nokia router on all downstream devices. Anything downstream may be assigned a /128 including your bridged router. However I need to check if its a 64 or 128.

Please recheck your v6 settings to confirm. Other downstream devices may be assigned a v6 by the Nokia provided you have switched off DHCPv6 on your personal router. At the most just keep RA on, letting the Nokia via Airtel's DHCPv6 do the work.

 

[doineedto]

@Chip forgot to mention that I am not on pfSense.
I am able to get a v6 for all the clients connected to the Nokia ONT. But we enable bridge mode just so that we don't have to use the Airtel ONT right! 😅
I thought that the bridged device is considered a separate connection, not a downstream of the Airtel ONT. So technically it should be getting a /64 address right?