Deco DHCP Server is passing my gateway along with manual DNS servers
Deco DHCP Server is passing my gateway along with manual DNS servers
Deco DHCP Server is passing my gateway along with manual DNS servers
2019-02-04 04:36:51 - last edited 2019-02-04 04:50:19

I've manually configured DNS servers for my LAN clients through the Deco DHCP Server, using Cloudflare's 1.1.1.1 and 1.0.0.1.  However, the DHCP server continues to pass my gateway address as a third DNS server.  How do I prevent this?

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#1
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24 Replies
Re:Deco DHCP Server is passing my gateway along with manual DNS servers
2019-02-04 19:42:06

@phireph0x 

 

That is strange.  I have a few questions to help isolate the issue:

 

1.  What is the make and model of your modem

2.  Is it a gateway device and if so is it acting as a gateway or modem?

3.  Is the WAN IP on the Deco a public address or a private IP?

4.  What is the DNS server address being used?

 

 

Thank you 

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#2
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Re:Re:Deco DHCP Server is passing my gateway along with manual DNS servers
2019-02-05 01:43:51 - last edited 2019-02-05 05:40:42

1.  TP-Link Deco M5

2.  Yes, my Deco is in router mode and is the gateway for devices on my network

3.  WAN IP is a public address, and I have my modem configured to do IP passthrough

4.  I'm configuring manual DNS servers and using

      Primary:  1.1.1.1

      Secondary 1.0.0.1

 

Yet my gateway address (192.168.x.1) is still showing up as a third DNS server.

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#3
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Re:Re:Re:Deco DHCP Server is passing my gateway along with manual DNS servers
2019-02-05 17:20:45

@phireph0x 

 

 

Do you have the address of the 3rd DNS?

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Re:Re:Re:Re:Deco DHCP Server is passing my gateway along with manual DNS servers
2019-02-06 00:14:25

192.168.68.1

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Re:Re:Re:Re:Re:Deco DHCP Server is passing my gateway along with manual DNS servers
2019-02-06 18:56:20

@phireph0x 

 

I spoke with our system testing engineer.  He would like to see what happens when you set the WAN DNS services to CloudFlare's.  Can you please make that setting change and let us know the results?

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Re:Re:Re:Re:Re:Re:Deco DHCP Server is passing my gateway along with manual DNS servers
2019-02-07 01:27:21

My WAN DNS servers are already set to Cloudflare's.

 

Primary 1.1.1.1

Secondary 1.0.0.1

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#7
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Re:Re:Re:Re:Re:Re:Re:Deco DHCP Server is passing my gateway along with manual DNS servers
2019-02-07 18:27:44

@phireph0x 

 

 

So we were able to replicate here locally.  We do see all 3 DNS servers coming up.  1.1.1.1,  1.0.0.1 and 192.168.68.1.  I am not able to tell you why or what the sigificance of the 3rd server is.  We will be engaging our system engineering team.  Though there will be a small delay in getting an answer from them.  It is currently the Spring Festival in HQ and the engineering staff is on holiday until 2/11.  As soon as we have word i will update this thread.

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#8
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Re:Re:Re:Re:Re:Re:Re:Re:Deco DHCP Server is passing my gateway along with manual DNS servers
2019-02-08 05:35:11

Thanks for the update, and glad to know that you were able to reproduce the issue.  Hopefully there's a configuration fix or firmware update forthcoming.

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#9
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Re:Re:Re:Re:Re:Re:Re:Re:Re:Deco DHCP Server is passing my gateway along with manual DNS servers
2019-02-11 18:20:34

@phireph0x 

 

 

Hi,  So my engineering team got back to us.  The reason there is a 3rd DNS is for optimization for some devices.  Iphones will check DNS settings before switching form LTE to WiFi.  Sometimes this switch will either be a slow connection or the connection will fail.  So, it an effort to optimize and help this situation a 3rd DNS was added.  

 

We understand this may casue issues for customers who manually configure their DNS servers so, the plan is to disable the 3rd DNS for any user who manually sets DNS servers.  While this plan still must past through the software team for final approval, if it does the update will be relased on the next Firmware.  

 

 

Best Regards 

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#10
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Re:Re:Re:Re:Re:Re:Re:Re:Re:Re:Deco DHCP Server is passing my gateway along with manual DNS servers
2019-02-12 02:52:13

That makes sense, and I'm glad to hear that the next firmware update will resolve this and remove the 3rd DNS server.

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#11
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