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TL R470T+ DNS timed out - Port unreachable

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TL R470T+ DNS timed out - Port unreachable

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TL R470T+ DNS timed out - Port unreachable
TL R470T+ DNS timed out - Port unreachable
2023-03-08 00:58:31 - last edited 2023-11-10 06:32:07
Model: TL-R470T+  
Hardware Version: V6
Firmware Version: 6.0.4 Build 20200313 Rel.32850

I have noticed random DNS timeouts with the TL-R470. Things work well initially but after 5 minutes or so I start getting DNS timed out (Port Unreachable) ICMP messages coming back.

 

My setup is two modems, one is a TPLink Archer VR400 V3 in bridge mode connected to the load balancer WAN1 port configured for PPPoE and the other is a Netgear LB2120 LTE modem in bridge mode connected the load balancer WAN2 port configured for Dynamic IP. I'm testing this setup with only one WAN port connected at a time but the problem occurs regardless of which modem is connected.

 

I assume the TL-R470 is acting as a DNS relay, passing the LAN client's DNS it recieves on to the DNS server address it gets from the connected modem's ISP settings. If I enter a value for Primary DNS=8.8.8.8 Optional field in the load balancer DHCP settings, the problem seems to go away because the DNS requests are no longer relayed by the load balancer, they are passed direct to the specified DNS address.

 

So, this is looking like a firmware bug in the TL-R470?

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#1
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8 Reply
Re:TL R470T+ DNS timed out - Port unreachable
2023-03-08 02:18:35 - last edited 2023-11-10 06:31:58

I suspect this post: https://community.tp-link.com/en/business/forum/topic/241734 is talking about the same problem

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#2
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Re:TL R470T+ DNS timed out - Port unreachable
2023-03-08 05:24:53 - last edited 2023-11-10 06:31:58

  @rossack 

 

Check this thread - your issue could be the same as the thread's OP.

If this was helpful click once on the arrow pointing upward. If this solves your issue, click once the star to mark it as a "Recommended Solution".
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#3
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Re:TL R470T+ DNS timed out - Port unreachable
2023-03-08 07:06:09 - last edited 2023-11-10 06:31:58

  @terziyski 

It looks similar but at the end of the thread it says: It was a Wan2 issue. for some reason it used the DNS of the other ISP 

I am testing with only one connection at a time and I see this behaviour regardless of the WAN port connection.

Something else I see with WireShark are error packets:

TCP Out-Of-Order

TCP Dup Ack

TCP Retransmission

 

It's ok to see these from time to time, but when you see lots of these when using the load balancer that makes it a prime suspect. 

 

 

 

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#4
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Re:TL R470T+ DNS timed out - Port unreachable
2023-08-04 09:20:18 - last edited 2023-11-10 06:31:58

  @rossack I am also facing same issue. any solutions? I tried with new load balancer as well. still same issue

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#5
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Re:TL R470T+ DNS timed out - Port unreachable
2023-08-04 10:53:51 - last edited 2023-11-10 06:31:58
Pretty sure its a firmware bug. I couldn't find a workaround so I ended up returning the modem and replaced it with an ER605 load balancer.
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#6
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Re:TL R470T+ DNS timed out - Port unreachable
2023-08-28 20:13:39 - last edited 2023-11-10 06:31:58

  @rossack same problem here. WAN1 only. New router, bought like 3 days ago.

 

For each new domain I enter (and sometimes for revisits) often but not always I get one of the following:

  • ERR_FAILED (without any other error) or
  • DNS_PROBE_STARTED then after a while DNS_PROBE_FINISHED_BAD_CONFIG

It feels like a timeout because after waiting like 1-2 minutes everything goes back to normal.

 

Until today I tried the following fixes:

  • Launched 3rd party computer cleaner, temporary shut down windows antivirus, did ipconfig /release, ipconfig /renew, ipconfig /flushdns, restarted router a few times, pushed cables, checked if anything is overheating, removed browser cache - no improvement, only temporary improvement after computer or router restart
  • Network -> LAN -> DHCP Client List -> reserved all DHCP clients IP's - no improvement so not a problem with IP change
  • Network -> WAN -> WAN1 - > entered Google's DNS: primary 8.8.8.8 and secondary 8.8.4.4 (before that there was my ISP's one autodetected) - some improvement but not much (at least I can work for 1-2 hours without brekas)
  • Transmission -> Load balancing -> Basic settings -> disabled load balancer - nothing improved so probably not the cause in my case (besides, I've got only 1 WAN)
  • Transmission -> Load balancing -> Online detection -> disabled online detection (set this to always online) - nothing improved so probably not the cause in my case

 

Today changed the following

  • Network -> LAN -> DHCP Server -> entered DNS and secondary DNS of Google in settings; after this change ipconfig /all shows DNS 8.8.8.8 & 8.8.4.4 instead of 192.168.0.1 

 

I'll post the result if something improves

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#7
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Re:TL R470T+ DNS timed out - Port unreachable
2023-08-29 04:08:59 - last edited 2023-11-10 06:31:58

  @DieHard1337 you have tried lots of options but it seems the DNS packets don't get past the load balancer or they get corrupted. There is also some timeout problem given everything works ok for a while but after about 5 minutes I start getting a high occurrence of DNS timeouts. I have tried different modems on different ports with dynamic and static DNS addresses, turn off load balancer etc.. using Wireshark to watch the traffic, but eventually had to give up. Unfortunately, there doesn't seem to be a workaround so unless there is a firmware upgrade we are stuck with a faulty router. TP-Link retailer was good in giving me a refund and I then purchase the ER605 which doesn't have this problem.

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#8
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Re:TL R470T+ DNS timed out - Port unreachable
2023-08-29 06:39:50 - last edited 2023-11-10 06:31:58

Hi @rossack and @DieHard1337 

 

First, the model is out of date and would not have any firmware upgrades any more unless a security upgrade. TP-Link End of Life Products and TP-Link End-of-Life Policy

So anyone who reads this, if you just purchased it, please return it and you can consider the new model Omada series, the entry-level one will be ER605. Also got other models, you can find more on our official website.

 

Second, 192.168.0.1, is the default DNS if you did not configure LAN DNS for your local network. This would be the common way to do it. There is a simple list of domain maps the IPs. And the router would pass it to the WAN DNS if it cannot resolve it. The LAN DNS would be the first queried DNS server you visit a site.

 

@DieHard1337 

What you've tried, basically none of them work except for WAN DNS and LAN DNS you've changed. Other settings are non-related.

 

 

I am not having any trouble with it. In the test buildup, I am using it to simulate the Internet. And there is no issue with the DNS resolving at all. I am using default gateway as the DNS.

 

I am on this version:

Best Regards! If you are new to the forum, please read: Howto - A Guide to Use Forum Effectively. Read Before You Post. Look for a model? Search your model NOW Official and Beta firmware. NEW features! Subscribe for the latest update! ☛Download Beta Here☚ ☛ ★ Configuration Guide ★ ☚ ☛ ★ Knowledge Base ★ ☚ ☛ ★ Troubleshooting ★ ☚ ● Be kind and nice. ● Stay on the topic. ● Post details. ● Search first. ● Please don't take it for granted. ● No email confidentiality should be violated. ● S/N, MAC, and your true public IP should be mosaiced.
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#9
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