DNS issue/ Request Firmware update?

[Splatt68]

Hi,

I recently changed over to the new SG4K100136 router to fix previous issue with my old router with blocked internal ports. Thats all working fine now.

On my network I have game servers deployed. Minecraft for my family and friends is the one that is causing the most issue. I have found when I restart the router I can connect to the server using its local ip 192.168.1.15:25565. This works fine for a day or so then it stops. However, People not on the home network can still connect using our no-ip domain using our public IP. After looking into the routers logs it seems to have issue with the internal DNS. For example 

01.05.2023 12:51:03

Error

DNS

DNS name resolution failure (_minecraft._tcp.192.168.1.15)

The work around I have at the moment (Which is not ideal) is to restart the router which then allow people on the local network connect and everything is fine.

I understand the whole net loopback thing and I'm fine with that as long as this can be resolved. I saw in a previous post that a firmware update can help resolve this issue?

My other game servers have similar issues such as Gmod. However its the same issue. Which makes be believe it is something router related. As soon as I put my old router back in it works fine and is stable.

Just for clairty:

• Ports are forwarded and are open and working for externals
• localhost works on the server but not on other local devices
• the local IPV4 works after a router restart but stops after a while

Anymore information needed please let me know.

[KeithFrench]

Hi @Splatt68 

If you are connecting locally via a hostname from a Windows PC to the Minecraft server, you could just issue this command from the Command Prompt, both when OK & when it fails:-

ipconfig /displaydns

If you get me the output from both times, that might help identify the problem.

This will be a lot simpler than a Wireshark trace:-

[KeithFrench]

I have also just written a programme that should help me replicate your issues, but I need to know the answers to the questions in my last post first.

Thanks.

[KeithFrench]

Ah sorry, I must have misread one of your replies.

From the way you say it, you are not trying to connect locally via a hostname, but always using the IP address & TCP port 25565. This will not be using the DNS server at all, however, the system log entry would tend to suggest that you are trying to use the domain:-

_minecraft._tcp.192.168.1.15

I doubt if the router is causing your issues.

The definitive way to find out what is going wrong is to take a Wireshark trace ideally on a Windows PC that connects locally to your Minecraft PC. All I will need you to do is to install Wireshark on that PC, take a trace with it, save it & upload it in a reply. I will do all of the analysis for you. If you are happy to consider doing this, I will provide you with full instructions on how to do this.

[Splatt68]

I do not have my own DNS server. I have tried setting it to googles DNS as well as Cloud flares DNS both yeild the same result. I have manually set clients to use the correct DNS settings aka point to the router as reccomended by previous forum posts. This did not fix the result. I have since changed this back to Automatic DHCP. 

[KeithFrench]

The only reason that the system log will display DNS errors is if you are using the router's own DNS server, but clearly, your clients are using your own third-party DNS server. Therefore, it looks like the network DNS server that your own DNS server is using is the router's internal server. Surely it would be more efficient & give you greater control if your DNS server connected directly to Google DNS, Cloudfare or openDNS servers etc.

[KeithFrench]

You are using your own DNS server on the LAN then?

Are you connecting to the Minecraft PC via a hostname or IP address?

[Splatt68]

Router - 5364

Main pc (192.168.1.69) Using 192.168.1.15:25565
Laptop (192.168.1.32) using 192.168.1.15:25565 when on local network. Public IP when away.

Server has reserved IPV4 192.168.1.15

Defult Gatway is 192.168.1.1 (Using the onboard DNS from the router. )

[KeithFrench]

I have just had another thought whilst trying to setup something to try & replicate your issues locally on my 5364. Do you have another Windows PC that you can connect to your Minecraft server with?

[KeithFrench]

The Sagemcom FAST 5364 or 5464 router both can run V136 firmware, the details you have given do not identify which one you have, although I would guess it is the 5364. Both will record DNS failures from any device on the network. What DNS server address is being used by your local devices trying to connect to the PC hosting Minecraft?

Your firmware is not up to date, the most recent at the moment is V158, but I doubt if that will resolve your issue. However, there is no harm in trying. I will ask TalkTalk to upgrade it for you.