D-Link Forums
The Graveyard - Products No Longer Supported => Routers / COVR => DIR-645 => Topic started by: Gamification on February 26, 2012, 07:10:12 AM
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I have two routers: a fritzbox that has an internal modem, configured with ip address 10.10.10.1
And the dir645, configured to connect to the internet using dhcp (gets 10.10.10.2 as ip- address from fritzbox). Internally i use a 192.168- subnet. There is a server in the internal network, that serves as a dns server. I can enter it manually in the clients and everything works. Dir645 can ping dns- server, dns- server can ping dir, i get to the internet, all ok.
But if i configure the dir directly to use this dns (in it's wan settings as primary dns, secondary is 10.10.10.1),then i can not reach thedns server via ping from the dir anymore and vice versa.
How can this be explained?
Thanx
Ah: why do i want to do this: i dont want to configure the internal dns server on any internet device...
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I have an idea what happens and would like someone to verifiy this:
Is it possible, that the DIR645 always assumes, that the DNS that I enter is external and therefor routes all requests to the DNS- Servers over the WAN- port?
That would explain, why I cannot ping the DIR anymore from my (internal) DNS- Server as soon as I enter it in the corresponding field (any other pings still work, from DIR to any internal IP, from any internal IP to the DNS server and from the DNS- Server to any other internal IP)
I guess, that DIR internally adds something like:
| Network Destination | Netmask | Gateway | Interface | Metric |
| 192.168.1.10 | 255.255.255.255 | 10.10.10.1 | 10.10.10.2 | 276 |
to its routing tables, with 192.168.1.10 = DNS- Server, 10.10.10.1 = External Gateway, 10.10.10.2 = WAN- Interface- IP
Is there any possibility to enter a DNS- Server that is in my local network or to change the routing to the dns server to go over the internal port (as it has an internal IP Address) and not the WAN- Port?
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Does the 645 have a DNS Relay, I wonder what happens if you turn that OFF.
You'll need to set up DNS on the PCs I believe and try.
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Setting dns on the device itself works... I was just distributing the dns settings via my old router so that i did not have to set it up on every network device (more than 10 devices, as everything has an ip- address nowadays....)
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DNS relay should work in the same manor on the 645 as well if ON.
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Sorry, but I seem to not explain the problem well:
1. I CAN set the internal Server as DNS- Server and it is distributed to the clients
BUT:
The DNS- Server then will not work anymore, because it can not reach its Default- Gateway anymore.
2. If I do NOT set the internal Server as DNS, then I have to set It manually on every client, but then everything works fine.
I guess, that the DIR adds a static route going through the WAN- Interface to every DNS- Server you enter, although the IP is in the LAN- Subnet....
I could connect the DNS- Server to the "external" router and give it an 10.10.10.x - Address, then everything would work as well, but as this server has different services it offers, I do not want that.
And I can not add an additional Network- card to the dns- server to connect it to both networks, as the mainboard has no free slot.
But I think. that my problem is not resolvable, as I can not change the way, the DIR does its internal routing...
Thank you for your help nevertheless
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Have you tried using the Beta FW v1.02 yet? Wondering if this might help or this is way that this router is designed. ALL i know is that leaving the DNS zero'd out under Setup/Internet/Manual, these routers are designed to automatically pick up DNS from the ISP. If you input something into the Manual setting, then the router should and will you those static addresses from there. And if DNS Relay is ON then it will pass any DNS information to the clients.
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I will try the BETA and tell you the result.
Again: The problem is NOT that the router does not use the DNS I entered or does not give it to the clients... The problem is, that it automatically tries to reach the entered DNS using the WAN- interface (what is not working, because the DNS is on the internal interface)... And it is independant of the setting in "DNS Relay"...
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Any status on this?
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I know this is an old post, but since I've been working on DNS issues lately I happened to look at the DNS configuration code in the router and can confirm that the router does indeed create a static route for every DNS server (configured either dynamically or statically) to go via the WAN port (or in the case of the PPP/PPTP layer, via PPP rather than directly via the WAN). (The only exception is if the DNS IP equals the PPP server IP.) It does not bother first checking if it is on the LAN subnet! Just thought I'd mention it.
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Thank you for sharing. Keep us posted on your DNS progress. ;)
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Oh one more thing - it does specify the routing table to add the route to explicitly as RESOLV. ie:
ip route add <dns> via <gateway> metric <def> table RESOLV
(Maybe earlier f/w releases didn't have the table option?)
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I know this is semi old however, I need to know if both of you are still out here and still exhibiting this issue with current official FW? We need to know if you have this resolved and what the current status is on this. Please let us know. Sorry it's taken so long to get back on this.
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I did not think that anybody would come back on this.
I did the following to resolve the issue: I bought another network- card for the dns server and attached it to the fritzbox directly with the 10.x subnet (found out that with a special raiser card I could get another pci card in the server). Then I configured firewall on the dns server to let only dns traffic pass through 10.x - Interface and set the 10.10.10.x address in the router to this (external) ip. Since then i did neither change my network- config nor did I update the dirlink as I follow the rule: never touch a running system (and it was alot work to get everything up and running).
If you wish me to do so, I could check, if the problem with the static route still exists with current firmware.
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Please verify if the problem exists in the current FW you have loaded.
What version is currently loaded?
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I am still on 1.02. will update this evening and check if it still exists...
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What region are you located?
Thank you for your information.
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I am in Germany.
Just tested, and it still does not work: As soon as i put in the 192.168.192.x Address as a DNS- Server, then it is not pingable from the dir-645 anymore...
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Ok, I'll forward this to my contact at D-Link. Please be patient to see if we can get any more information.
Thank you.
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Just one thing: I made a backup of my configuration before updating. But I could not use it after update (not compatible). So I had to set up everything (ip adresses, routes, dhcp reservations, etc. etc. ): I needed 3 hours for that...
Please inform me, if an update will recommend to do this again, then I will write out all the information...
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Yes I also noticed this going from v1.02 to v1.03. Had to set everything up again while using v1.03.
I recommend that you take screen shots of any configurations on the routers web pages from prior versions for safe keeping.