Author Topic: DNS Problem  (Read 6137 times)

pronto

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DNS Problem
« on: December 03, 2015, 06:51:58 AM »
Hi Community,

we are using a WZR-HP-G300NH2 with Firmware DD-WRT v24SP2-MULTI (06/03/12) std - build 19154 as Access Point for our WIFI mobile devices (smart phones, Laptops ect.). The buffalo device works as a router and the internal NIC is configured as a seperate LAN (192.168.11.0/24) in NAT mode and the WAN interface is configured with an IP address from our local subnet of our internal LAN. Please note draft and screenshots below.

The problem is that we cannot resolv IP addresses from internal resources from a WIFI connected mobile device but only external addresses. So we can reach www.google.de without problems but we cannot connect to wiki.domain.de with an internal IP address (192.168.110.100). When we sniff the traffic with tcpdump on the Buffalo box we can see that the DNS request leave the Buffalo box to the right DNS server and we can see also a correct answer from the DNS server to the Buffalo box but the name resolution won't work anyway.

We are pretty sure that the problem is located in the Buffalo box but we have no clue where the misconfiguration is.  Any hints?





Thx & Bye Tom

 

jasonlinte

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Re: DNS Problem
« Reply #1 on: December 07, 2015, 12:26:22 AM »
I also want to know how to solve this problem. This is a hard problem for me to solve by myself.

davo

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Re: DNS Problem
« Reply #2 on: December 07, 2015, 07:13:04 AM »
You need to enable NAT Loopback on the router.

Administration -> Commands -> Enter the Below command -> Save Firewall.

iptables -t nat -I POSTROUTING -o br0 -s 192.168.11.0/24 -d 192.168.11.0/24 -j MASQUERADE
« Last Edit: December 15, 2015, 03:34:47 AM by davo »
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pronto

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Re: DNS Problem
« Reply #3 on: December 14, 2015, 04:53:08 AM »
Servus Davo,

iptables -t nat -I POSTROUTING -o br0 -s 192.168.11.0/24 -d 192.168.11.0/24 -j MASQUERADE

no this won't help. We are not sure which problem you try to fix with your enable NAT loopback command. Your command maybe makes sense when the network connection won't be established but in our issue the connection is up and running and the DNS resolves every external address without problems but it failes to resolve internal addresses. The DNS server is reachable anyway.

Can you explain the idea behind your fix?

Thx & Bye Tom

Walterschafer

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Re: DNS Problem
« Reply #4 on: May 18, 2021, 04:31:31 AM »
Can anyone help me with this problem so basically it shows that I have internet access but when I go to any website it says "no internet" I opened windows network diagnostics it says "The DNS server isn't responding can anyone help me, please?
Updated: yesterday a friend of mine suggested to me this guide which completely solved my issue.
« Last Edit: May 19, 2021, 08:05:32 AM by Walterschafer »