[Dev][Feedback] Changing DNS behaviour on router

[RMerlin]

Heya,

I am considering reverting back resolv.conf to match what Asus uses in stock firmware, which is to always use the DNS servers rather than 127.0.0.1 (which means always use dnsmasq). Primary reason would be this might be more robust for weird ISPs who use a DHCP + VPN type of architecture (as after the DHCP lease is obtained, it typically uses a special "temporary" DNS server that can resolve the ISP's PPTP/L2TP hostname).

The primary side effect of this is the router itself will no longer be able to resolve LAN hostnames. The most visible effect for end user is netstat-nat (on the webui) would no longer resolve LAN IPs into LAN hostnames (but it would still work for public hostnames).

Any impact on the existing scripts out there that are run on the router itself? Does any of these require to be able to resolve LAN IPs and hostnames?

 

[Treadler]

This is a little above my pay grade, but, here goes.
Would this change be the same as having dns filtering=on, & global filter mode = router?
(Without any custom dns necessarily specified).

 

[dave14305]

This is a little above my pay grade, but, here goes.
Would this change be the same as having dns filtering=on, & global filter mode = router?
(Without any custom dns necessarily specified).

This change would not affect LAN clients resolving hostnames (internal or external). Just when the router itself wants to resolve a hostname (e.g. for firmware update check).

 

[popxunga]

Primary reason would be this might be more robust for weird ISPs who use a DHCP + VPN type of architecture (as after the DHCP lease is obtained, it typically uses a special "temporary" DNS server that can resolve the ISP's PPTP/L2TP hostname).

Hi...
Just curious... how many of us are using those weird ISP's services ?
Thanks

 

[RMerlin]

Hi...
Just curious... how many of us are using those weird ISP's services ?
Thanks

Not many. The only ISP I heard of is Beeline in Russia.

 

[TheUntouchable]

Just for my understanding: It would not be possible anymore to check with a script on the router if a specified decive hostname is resolvable/reachable?

 

[Ronald Schwerer]

While I don't pretend to fully understand the impact of RMerlin's proposal, I have a question. How would this impact the use of the etc/hosts file for local name - IP resolution? I sometimes use that mechanism to override DNS lookup.

 

[RMerlin]

While I don't pretend to fully understand the impact of RMerlin's proposal, I have a question. How would this impact the use of the etc/hosts file for local name - IP resolution? I sometimes use that mechanism to override DNS lookup.

That's a separate issue. On older models it won't make any difference. HND models however (RT-AX88U and RT-AC86U) will require a separate fix to make these works properly. That's stricly for router-based resolution however, your LAN clients going through dnsmasq will still behave 100% like before.

 

[RMerlin]

Just for my understanding: It would not be possible anymore to check with a script on the router if a specified decive hostname is resolvable/reachable?

It will mostly affect name resolution. You can still use a device's IP to ping it, for instance.

 

[popxunga]

Not many. The only ISP I heard of is Beeline in Russia.

If that's the case, I would keep the current design option and not align with ASUS, because I'm quite sure that such a modification may break a significant number of our current setups.

 

[chris.at]

I'd also keep the current design which allows local name resolution within router cli and scripts. I'm using names in some scripts for devices with dhcp addresses in my lan.

 

[themiron]

Not many. The only ISP I heard of is Beeline in Russia.

not true. millions of users

 

[themiron]

Just for my understanding: It would not be possible anymore to check with a script on the router if a specified decive hostname is resolvable/reachable?

unrelated

 

[themiron]

If that's the case, I would keep the current design option and not align with ASUS, because I'm quite sure that such a modification may break a significant number of our current setups.

can you give any example of such setup please?

 

[RMerlin]

Just for my understanding: It would not be possible anymore to check with a script on the router if a specified decive hostname is resolvable/reachable?

If you use nslookup, you can also specify a nameserver to use (in your case, 127.0.0.1).

 

[RMerlin]

not true. millions of users

Know other ISPs still using this?

 

[john9527]

I use ping by name in a dnsmasq dhcp-script to provide ipv6 local name resolution on my fork. I won't be making this change.

 

[Goobi]

My vote is to keep local name resolution as I actively use it in my environment.

 

[ColinTaylor]

My vote is to keep local name resolution as I actively use it in my environment.

You use it on the router, not the LAN? What for? Could it be worked around?

 

[Goobi]

You use it on the router, not the LAN? What for? Could it be worked around?

Ah, misunderstood when reading. No, I just use it on the LAN not router so I would not be impacted by this change. Thanks for pointing that out.