RVS4000 > Set ROUTER to use custom dns?

[aaron.martinas]

here's my situation:

my ISP assigns me a dynamic ip address. this is pretty standard. along with my IP, i receive my DNS settings as well. this is completely normal. i totally understand this.

however, i wish to use CUSTOM DNS. in windows, i can accomplish this very easily. in the "network connections" window, i select the properties of my network adapter. if i change the properties of the TCP/IP protocol, i get the dialog that is present in the "windows.png" file attached to this post. here, i am able to ensure that my computer receives the dynamic IP, but i then overwrite the DNS and use my own.

simple.

i want to do this on my RVS4000 router. i want to set up custom dns as the subject implies.

before you start screaming about the "Server Settings (DHCP)" section in the "lan" tab under "setup", this is NOT correct. why, you say? because when you set this up this way, the DNS information is forwarded to the DHCP clients. this does NOT change the ROUTER'S dns. i want to know how to change the ROUTER'S dns.

again, using the windows scenario i described above, i should be able to tell the ROUTER to use a custom DNS. BUT WAIT! before you scream "use the Internet Connection Type" in "wan" under "setup", consider the fact that i have a commercial ISP and that i HAVE TO USE DHCP to get an IP and connect to the internet. and belive me, i've already tried workarounds... i set my router in DHCP, got an address, then without rebooting the ISP's modem, i changed my "internet connection type" to "static ip", using the information i got when i was in dynamic mode. THIS DOESNT WORK. PERIOD. THE INTERNET DOES NOT WORK, DESPITE THINKING IT SHOULD. im sure the ISP is forcing something down my throat. also, even if this DID work, this would be COUNTER-INTUITIVE. why? because if my ip were reallocated, i would lose network connection. by design, i should use DHCP, and i shouldn't try to circumvent it.

so now that i've clearly explained the issue and all the hurdles, how can i set up custom DNS on my router while in DHCP mode (just like windows has APTLY SHOWN IS EASILY POSSIBLE SINCE PROBABLY 1995)???

another question you may be asking yourselves-- why not just let my clients get the custom DNS and be happy? because i have some internal network names that i still want to have access to. if the clients have the custom dns shot directly to them, they will never be able to resolve those internal names. if i can just tell my stupid router to use custom DNS, the clients still use the router as their DNS, and when the router receives the requests, it can then determine if DNS request is internal and send it to that nic, or if it needs to go outside.

I'd REALLY appreciate CISCO response on this

[David Carr]

The rvs4000 does not have that feature.    When you obtain an ip address on the wan you get the dns server that is given.  Cisco knows of the product limitation.

[aaron.martinas]

excuse me for asking the obvious question, but considering the simplicity in implementing this combined with the obvious necessity, why is this a "product limitation"?

[Gerald Vogt]

Because for routers which are only configured through a web interface you always have the design issues between an additional feature and the simplicity of the interface. There are many features which would be useful in some scenarios but are not supported even though it would be very simple to add it. Some things you add and some not. Thus there are "product limitations". It makes configuration simpler. It makes support easier.

Or taking this to the extreme: they could open a full root shell access to the Linux on the RVS. Then you can configure pretty much anything you can think of. You could overcome any limitation in the web interface. But that would make support extremely expensive as you have to deal with problems based on very complex configurations.

You see these "product limitations" everywhere. It's just a trade-off in design.

[aaron.martinas]

g_v, that doesn't really answer the question. at best, what you said simply gives excuses for not doing this. why was it determined that being able to set the DNS in addition to leaving my router in DHCP was not implemented? honestly, the simplicity or non simplicity is a non issue as this question goes... simplicity simply gives an extra reason that this should already be available. but beyond that, it is not a reason in and of itself for lack of implementation one way or another.

the point of the windows explanation in my OP was simply to indicate that this CAN be done, HAS been done, and most importantly SHOULD be done.

so the more concise question is why was this intentionally made as a product limitation?

[tomwallin]

WOW! Really?

It was just explained that Cisco is not gonna change the feature.

Try another router, either Cisco's or someone elses. This ranting will not get you what you want. :-)

[aaron.martinas]

yes, really.

you only explained that some features exist in some grey "not going to be supported" area. but you didn't give the official "why it is in this self imposed grey area". i want to know why. and since youre not cisco staff, i understand why you're not able to provide a technical answer.

this is still answered. please provide an actual technical reason as to why this isn't implemented. the cisco rep's "because we haven't supported it" answer is not sufficient. why isn't it supported? what technical reason?

[johnacla · Accepted solution]

Aaron,

        I understand your frustration, and would like to assist. If possible, can you send me your email address as I would like to setup a time to discuss one on one with you.

Thank You,

John Clark

[aaron.martinas]

i was unable to find a "pm" system, so here's a temporary address for me:

il5b-jk8n@spamex.com

it's a disposable address so it is of no consequence to me that it's posted out in the open

[tomwallin]

John, John, John. You must be a saint. :-)

[tomwallin]

I didn't explain why Cisco won't add your feature. I was just really agreeing with gerald_vogt about a corporation's decisions with adding features. They're not excuses. Decisions are made for various reasons and some, no alot, of those choices were explained by g_v. And yes we are not Cisco. But I read alot of whys as to the reasons for not including YOUR feature.THE technical reason was explained - "Or taking this to the extreme: they could open a full root shell access to the Linux on the RVS. Then YOU can configure pretty much anything you can think of. You could overcome any limitation in the web interface. But that would make support extremely expensive as you have to deal with problems based on very complex configurations."

It looks like your squeky wheel has got Cisco to talk to you. Why they would do that makes me think that they are really trying to oil your wheel. And show that they care.

Answer me one question - What makes you so entitled? Rich, only child. Again, $150 does not buy you a corporation. Why don't you just design implement and support your own router. All for $150 a piece.

[Gerald Vogt]

It's not an excuse. There is no "grey area". It is a question of design. It's everywhere. Many things can be done and are not done. It is futile to ask for an detailed explaination why it was done this way or that way. You will never get an official answer to that.

There is no grey area. There are a lot of features that would be useful sometimes and have not been added although it was easy. Starting this disussion is futile. It will never end. There is always someone who needs a "simple" feature which is missing. It will go on and one.

Why does the router only supports LAN subnet mask /24 and smaller?

Why does it not allow you to configure the source addresses to go through NAT?

Why can't you configure multiple local/remote security groups for IPSec tunnels?

Why can't you change the user name to log into the web interface?

Why can't you add additional users for log in?

Why can't you set the default gateway if the internet port is down?

Why can't you assign your own gateway through the DHCP server?

Why, why, why???

Why is there no root shell access to the router to configure anything you want without limitations of the web interface?

Do you really expect an answer to your questions and all those questions that will follow? It will never stop.

It remains as it is: any feature, any option added to the web interface adds complexity in software implementation and possible configuration. And this makes support more complex. It does not matter how difficult or easy it can be done. It does not matter if it looks easy in Windows. If someone has DNS trouble with the router and calls the support it would be one more thing to consider and check.

If maybe one person in 1000 needs the feature you need, it won't get implemented. Noone now exact numbers thus you'll make your design issues based on questionaires or other feedback. But for devices very tight on budget and support you won't add a 1:1000 feature because pretty sure if you would there would be at least 10 people you accidentally configure it wrong and then call for support.

You see that with the Windows IP dialog: I have seen too often that people played around with static IP, DNS, gateways, etc. and in the end did not figure how to undo everything, leaving static DNS or gateway on their computer. Everything worked fine until they have switch to a new brand router who happens to use a different LAN IP subnet. Now your DNS proxy and gateway is not at 192.168.0.1 anymore but at 192.168.1.1. That's is one of the effects of the complexity of the Windows dialogs. Of course, Microsoft does not really bother because they don't do the support for problems like that.

There is no grey area. There are no excuses. If a router does not have the feature you need you've bought the wrong router. These cheap routers always have lots of limitations. If you have advanced requirements get a Cisco with an IOS CLI or similar.

[Alejandro Gallego]

"another question you may be asking yourselves-- why not just let my clients get the custom DNS and be happy? because i have some internal network names that i still want to have access to. if the clients have the custom dns shot directly to them, they will never be able to resolve those internal names. if i can just tell my stupid router to use custom DNS, the clients still use the router as their DNS, and when the router receives the requests, it can then determine if DNS request is internal and send it to that nic, or if it needs to go outside."

I know this is very late, but just happen to catch my eye....

First, the RVS is not a DNS server and will not cache DNS (may be wrong). Setting the router to answer DNS querries for other devices inside the LAN will never happen unless you have a DNS server for your network. Right now if you are resolving names internally with out a DNS server, this is happenning via NETBIOS.

Now as to why is your feature not supported. Well because that feature is on a more expensive device that is meant for a larger network. Large networks would have a need exactly as you described.

Setting the "Custom" DNS setting under DHCP will give you what you want, and all DNS querries will go exactly there, regardless of what your ISP gives you. If you feel that is NOT happening, use "nslookup" and post results. For your internal names to be resolved, make sure you have NETBIOS enabled on your computers (assuming this is a Windows environment) and you should still be able to do so. An other option would be to assign DHCP reservations to your clients and build a "host" file. Once it is built just install it on your PCs and you are done. PCs will always look at the "host" file before sending a DNS querie.

Remember, with no DNS server there is no "A" record, if there is no "A" record there is no DNS querrie to be resolved. NETBIOS and DNS are sepparate and do not interfere with each other.

Like they say better late than never.

shameless plug:

http://opendns.com

[aaron.martinas]

in the writing of this post, i realized (to some extent) exactly why my comptuers are no longer able to resolve netbios names when i have to use CUSTOM DNS passed to clients as DHCP:

http://support.microsoft.com/kb/172218 (see the section titled "Host name resolution generally uses the following sequence:")

when my ROUTER receives its DNS servers (because the ROUTER is in DHCP mode), it uses those DNS servers whenever it receives requests on port 53. it sends ITSELF as the DNS to any DHCP clients. therefore, when a windows client sends a name request, it follows the order above. wth the ROUTER as the DNS server, the following will occur:

1. client checks to see if the name is itself. the answer is no.

2. the client checks the host file. the name isnt found.

3. dns is attempted. the router for WHATEVER REASON does not forward the request out to the ISP's dns server. DNS FAILS.

4. the computer attempts to do netbios resolution. SUCCESS!! EVERYONE'S HAPPY!!

however, when i send the windows CLIENTS the EXTRENAL DNS servers (which is NOT WHAT I WANT!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!) this happens:

1. client checks to see if the name is itself. the answer is no.

2. the client checks the host file. the name isnt found.

3. dns is attempted. THE CLIENT SENDS THE REQUEST OUT TO THE DNS SERVER, AND THE SERVER IS LIKE WTF IS THIS!? either the server responds "are you stupid?" and resolution fails, or the server responds "yea, here's a 'portal' IP address". which is INCORRECT ANYWAY!

4. netbios is never attempted. FAIL FAIL FAIL FAIL FAIL!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

alegalle wrote:
First, the RVS is not a DNS server and will not cache DNS (may be wrong).

this is already a red flag. and then you go on to expound on this as cisco rep? im sure that what you said applies if in fact it ISNT a dns cache, but that just really adds a lot of dubiousness to your technical prowess.

alegalle wrote:
Right now if you are resolving names internally with out a DNS server, this is happenning via NETBIOS

i am more than aware of this fact.

alegalle wrote:
Setting the "Custom" DNS setting under DHCP will give you what you want, and all DNS querries will go exactly there, regardless of what your ISP gives you.

which is exactly my problem. i want the ROUTER to NOT send the DNS request so that netbios CAN OCCUR.

alegalle wrote:
An other option would be to assign DHCP reservations to your clients and build a "host" file. Once it is built just install it on your PCs and you are done. PCs will always look at the "host" file before sending a DNS querie.

fail. this involves going to each client (wether manually or programatically) and setting up names in their hosts file. i dont run a domain, so my only central location of network traffic is the RVS. when the RVS is sent to the DHCP clients as the DNS server, EVERYTHING WORKS PERFECTLY! but becasue i want to use custom dns (opendns, btw), EVERYTHING FAILS FOR THE REASONS i noted above.

alegalle wrote:
Now as to why is your feature not supported. Well because that feature is on a more expensive device that is meant for a larger network. Large networks would have a need exactly as you described.

this is not an acceptable answer. it MAY IN FACT be the cisco answer. but to say that it's meant for more expensive devices? just to be able to tell my router that instead of using the DHCP provided DNS servers, to use custom DNS? that cant be that damn difficult.

FURTHERMORE, i can go out and buy a copy of windows XP for 90 dollars and tell it to use DHCP but with CUSTOM DNS without being "enterprise" and still get the functionality of using DHCP without using DHCP suggested DNS servers.

and my BUSINESS CLASS rvs4000 cant WONT let me do this??

asinine.

[Alejandro Gallego]

Note to self:

Never answer Flame Posts

Never "Assume"; as I am all too aware of what it does.

First was my mistake to answer an already heated post which does not really seem to be looking for resolution. My second mistake was to assume that needed steps might have already been taken, I should have asked for more information.

You provided this link http://support.microsoft.com/kb/172218 but fail to point out a very important piece; "Unless you change the order in which lookups occur."

From your post I assumed you had already done a great deal of work and this had already taken place. Also, since you read that MS article you also understand that DNS has nothing to do with NetBIOS. The problem is not on the router nor on your network. The problem is that NetBIOS is deprecated and systems like XP and above much rather use DNS.

My statement about the router was meant more as sarcasm, which I should have left out. The RVS does not cache DNS nor is it a WINS server. Your router will in fact use the DNS servers it receives on the WAN port, unless you specify what DNS servers clients are to use when the router hands out DHCP on the LAN. If you specify OpenDNS on the DHCP scope for clients, the clients will send DNS there NOT the router. If you leave the DNS fields blank the router will send itself as the DNS server, and in turn forward the request to your ISP. So, whether or not you are able to apply your custom DNS settings on the WAN is of no consequence since you have not made any concessions on your clients to resolve NetBIOS first. But you did point this out:

"fail. this involves going to each client (wether manually or programatically) and setting up names in their hosts file. i dont run a domain, so my only central location of network traffic is the RVS. when the RVS is sent to the DHCP clients as the DNS server, EVERYTHING WORKS PERFECTLY! but becasue i want to use custom dns (opendns, btw), EVERYTHING FAILS FOR THE REASONS i noted above."

Well since you can specify a primary and a secondary DNS server, why don't you specify the router as DNS 1 and OpenDNS as DNS 2. Would this not solve your problem?

Since you are using OpenDNS you may be seeing some different behavior when clients have OpenDNS as a DNS server. May be like this:

LayOff2:~ $ ping layoff

PING layoff.charter.com (208.67.217.132): 56 data bytes

64 bytes from 208.67.217.132: icmp_seq=0 ttl=50 time=33.993 ms

64 bytes from 208.67.217.132: icmp_seq=1 ttl=50 time=33.541 ms

64 bytes from 208.67.217.132: icmp_seq=2 ttl=50 time=32.919 ms

64 bytes from 208.67.217.132: icmp_seq=3 ttl=50 time=33.252 ms

64 bytes from 208.67.217.132: icmp_seq=4 ttl=50 time=45.583 ms

64 bytes from 208.67.217.132: icmp_seq=5 ttl=50 time=48.611 ms

Does that look familiar? That address is not me, it is OpenDNS, and it replies to my other Mac which is on my LAN well behind other equipment. But now lets change DNS server:

LayOff2:~ $ nslookup

> server 4.2.2.2

Default server: 4.2.2.2

Address: 4.2.2.2#53

> layoff

Server:4.2.2.2

Address:4.2.2.2#53

** server can't find layoff: NXDOMAIN

Now just like that there is no resolution. Why?

=======================================

Current systems do not make a lot of concessions for NetBIOS so having a hard time with this nowadays is not surprising; and I do understand your frustration. Just think, all of this could have been avoided if you would have changed the order of Name Resolution on your clients.

'FURTHERMORE, i can go out and buy a copy of windows XP for 90 dollars and tell it to use DHCP but with CUSTOM DNS without being "enterprise" and still get the functionality of using DHCP without using DHCP suggested DNS servers.

and my BUSINESS CLASS rvs4000 cant WONT let me do this??

asinine."

In your closing statement I feel just a lot of frustration and no real direction. If this thread was to find an answer to a problem, I would recommend a better approach. If you just meant this to be a way to suggest added features to the RVS, you should have made it a discussion. Your example of XP I must comment on; XP is not a router, and you can do exactly as you stated; however, in its default state it is not a router nor can it hand out DHCP addressing.

Then you finish (along the way insulting others) stating how "" it is that your RVS does not support this feature. That would be the same as going back to my Honda dealer and completely insult, yell and show them how wrong they are for not telling me why my 2009 Honda Civic LX does not have a 6 speed transmission, when the red Civic SI right in front of them does. "Can't you not put that transmission in my LX, Does Honda really know what they are doing......??"

Which that was the "Question" all along, and I fell for it. This thread needs to be closed or moved, because there is nothing helpful here and it was never meant as a means to ask for assistance nor to suggest a feature set.