Zyxel PMG5617-R20B: Struggling with DNS

[LonerPrime]

Hi everyone,

Long time reader, first time poster here. Foremost, thanks for having me.

Some context first: I've been on Airtel XStream fibre for some few years now. Last April, they updated the cabling network near me and then paid a visit to my home informing me that my original Huwaei router had to be replaced as it was no longer compatible with Airtel's newer standard. While I didn't really buy it, given that the router belonged to them in the first place, I didn't really object when they replaced it with a ZyXEL PMG5617-R20B variant.

Unfortunately, I started observing peculiar behavior soon after. On odd occasions, websites won't open up, or will be slower or the router would go AWOL for a few minutes while I was working at night and then mysteriously come back. While issues only cropped every now and then, recently, I had it and did some investigations.

Now I'm not an expert at this, but I have some experience so please bear with me- These are my Windows LAN settings:

As you can presume, I don't trust Airtel's DNS network. It's slow and tends to be clunky on the best of times. So I use Google or Cloudflare DNS, and with my last router, that'd work seamlessly. Unfortunately, this Zyxel feels like it has been heavily customized by Airtel and not in the best of ways. While my "ipconfig /all" showed that my LAN is indeed passing requests to Cloudflare DNS, the router itself however is doing this:

Down below, there are four options in the DNS Values:

1. Obtain from ISP
2. UserDefined
3. DNS Proxy
4. None

The first, second and fourth are clear. The first one will straight up pick Airtel's own DNS server, the second will be the one I assign as user and the last one will pick no DNS server. By default however, is the 3rd one i.e DNS Proxy- which is a stranger to me. I can only speculate that since the IP assigned here is my own router's IP, it will by default request network traffic to route via Airtel's DNS.

If so is the case, I'm not a fan and would rather it didn't as it could explain the wonky web behavior. But here is where my problem comes in:

Any attempt on my end to change the DNS here by switching to "UserDefined" Mode is thwarted by a lack of any option button equivalent to "Okay" or "Apply". Experience dictates one should show up right next to Cancel button on the bottom right after I set the DNS value, but... nothing.

Now I've got in touch with Airtel and for some mysterious reason, they are stumped as well. First the guy tried from his own end, but failed. Then a tech visited me at my place but failed as well. He then came to the conclusion that only the NOC staff can make this happen, which seemed extremely odd to me. Why would a router deny the end user such a basic functionality? But Airtel doesn't exactly staff the most "knowledgable employees", so I didn't push the matter with him and they are now currently, and I quote, "working on the issue".

Meanwhile, I also went looking on the internet for any similar discussions, and tripped on two Reddit posts that were made as recently as 7 months and the other 1 year ago from Airtel users with the same intent

#Reddit Post 1
#Reddit Post 2

While most of what was in those threads were speculation at best, but one thing that did catch my eye was the claim that this particular router model had lost this DNS and other functionality some time ago during a firmware update from Airtel, something which is imposed upon you after each router restart. While a compelling theory, I was hoping if someone here had their own take on this matter. I don't have much high hopes from Airtel actually coming through with a proper resolution in this regard. Infact, I wouldn't be surprised if they just up and call me and say "Your internet is working, so all is fine. Please stay calm and keep paying."

Jests aside, I'd appreciate it if someone could weigh their opinion on the matter.

Thanks and Regards,
LonerPrime

 

[LonerPrime]

While I understand I made the post yesterday, things kind of moved quickly in the last few hours that I ended up making some snap decisions. So, here is a final update:

After being turfed from one tech to the other, Airtel NOC finally made the admission that, and I quote,

"We are sorry sir, but we do not have the authority or control to assign you your desired DNS server. If you are facing any browsing issues, we can try and troubleshoot that."

Typical and expected to be honest. Apparently, not only the end user, but even the ground staff AS WELL as the NOC team are forbidden to make even the basic changes to the router now. Tech is evolving, but backwards? "You will deal with Airtel DNS and you will like it." Well, screw that.

On the spot, I asked them to switch the ONT into bridge mode instead. The tech tried to convince me that a static IP is needed for that, but I was having none of it and told him to talk to his superiors while I went to the local store to buy my own router. Found a TP-Link AX10 at a neat price and by the time I was back the tech informed me that the bridge mode has been activated. At least they are quick to act, if nothing else.

It took me barely 10 mins to set it all up. Would have been quicker if I didn't had to go fishing for PPPOEE credentials in airtel's router and the bill. But in the end, it was seemless and DNS started routing via Cloudflare in no time.

Morale of the Story: Don't let ISPs decide what you can and cannot do with your own device. Even if it's free, the fact that they control access to my router never sit right with me in the first place, but then they started messing with my browsing experience by forcing subpar settings and I was done. Not exactly an elegant solution, spending money just so you can have your own DNS preference, but having your own device and control is worth it. Not to mention I can use my TPLink in the future with other ISPs as well.

 

[d4rk4shes]

Hi, could you please tell how you found the PPPoE creds? Doing the same as I am tired of their crappy DNS Servers

 

[tr1k0N4]

Check at the bottom of the Airtel Xstream section in Airtel Thanks app.
Your DSL number is your username and your account number is your password.

 

[kizmat]

Oh wow, ran into the same issue today and found your post through Google!

In my case, I am running a local pi-hole (Pi-hole – Network-wide Ad Blocking) DNS server, and wanted to change the DNS setting on the router. Saw the exact same thing that you are - the configuration page has no way to save the new DNS server! My support experience has also been almost exactly the same as yours - technicians have visited me twice, they acknowledge the issue, but the backend team is not able to do anything about it! I spoke with the backend person, and he couldn't wrap his head around why I would want to change the DNS server (it's my network man, let me do what I want!).

From your post, it seems like a lost cause. What if I ask them to replace the router? That might help.

 

[f3rmion]

For anyone using a solution like pihole, adguard home or technitium dns, simply turn off dhcp from the router and enable it in your sbc running the ad blocking software. For others who don't have such a setup, use the Private DNS option on your smartphone and DNS over HTTPS on windows 11. Most modern browsers have inbuilt DoH provision. just check your browser settings.

 

[tr1k0N4]

It's a lost cause, brdr, @kizmat. They have locked a shit ton of their routers already so asking for a replacement won't help.
If you have budget, get your own equipment. TP-Link XX530v is a good option if you want a XPON WiFi 6 router for about 4299.