CradlePoint CTR350 - DNS Poisoning Has Occured

muzicman82 · EVDO User Joined: 13 Dec 2005 Posts: 65

So, I've setup my CTR350 with most of the default settings. One exception is that I'm using OpenDNS DNS servers instead of Sprint. I leave the router powered on at all times, and simply pull my Novatel U720 when I leave every morning and plug it back in when I get home. My desktop PC is hooked up to the CTR350 via Ethernet (I am using the new firmware!).

On the desktop, after the card dials, I get a CradlePoint page saying "DNS Poisoning Has Occured" and it tells me to restart my browser. Well, restarting the browser doesn't work, nor does refreshing the IP. I can only get it to work if I power cycle the router. If I remember correctly, the WLAN side operates just fine.

It's not a huge deal since the thing powers up so quickly, but not having to power cycle is one of the many reasons I ditched the KR1 for the CTR350.

Any one else seen this?

sbonar · EVDO User Joined: 13 Nov 2007 Posts: 84

Have you tried using Sprint's DNS servers instead of OpenDNS. I've heard that Sprint actually blocks any DNS packets other than their own.

muzicman82 · EVDO User Joined: 13 Dec 2005 Posts: 65

Well it doesn't make sense then why it would work after a power cycle if blocking has occurred. It was first suggested to me to use OpenDNS on this forum back in the day to speed up things a tad. I used OpenDNS with the KR1 with no problem.

Not sure yet if I'd get the error with Sprint's servers.

visortgw · EVDO User Joined: 28 Oct 2005 Posts: 67

Are you sure that OpenDNS is actually providing DNS services? After you reboot the router, navigate to https://www.opendns.com/start to verify whether OpenDNS is really active -- you should see "You're already using OpenDNS! Go to Step 2 and create an account to get more benefits (optional)."

muzicman82 · EVDO User Joined: 13 Dec 2005 Posts: 65

Yep, its OpenDNS alright.

herlien · Posted: Fri Jan 11, 2008 10:42 am Post subject:

Same thing happens to me periodically. I haven't been able to determine what sequence of events causes it to happen, though now that you mention it, I think it's whenever I power down & power up the Cradlepoint. CTR350, Sierra Aircard 595U, and I have my desktop & laptop set to use OpenDNS.

It's pretty frustrating, because shift-refresh and ctl-refresh don't seem to help, though retrying enough times will usually eventually cause it to go away.

Last time it happened, I opened a DOS window and executed:
C> ipconfig /flushdns

That seemed to have worked.

Hardware · EVDO Heavy User Joined: 07 Dec 2007 Posts: 141

This usually fixes DNS resolve problems.

Close all your browser windows.
Open a DOS Prompt (Start, Run, "Command")
Type "ipconfig /flushdns"

Try again.

Capt Ron · Posted: Fri Jan 11, 2008 11:27 am Post subject:

I added Open DNS to my CTR350 about a week ago and have been using it ever since. The last couple of days I noticed my speed had slowed down. A speed test showed I was getting only around 100 to 200 kbps down load speeds.

Connecting my modem to my laptop, the speed went to 500 to 900 kbps. So I went back to default DNS and the speed jumped up to 500 kbps through the CTR350.

I've noticed that my speed isn't ever as fast through the router.

byrd · EVDO User Joined: 21 Dec 2007 Posts: 49

I've been having similar problems. At first I thought is was the modem, but now am fairly sure that it's my CTR-350. I posted this thread last week over in the Modems forum, but assistance was scarce: http://www.evdoforums.com/thread7861.html

I was just about to repost the thread over here but then I saw this thread.

I typically leave my modem up and running 24hours a day, but about once a day, I wind up loosing my DNS settings. So far I haven't been able to solve the issue. I can bring up a command prompt and ping just about anything that I'd like, but cannot view any web pages. I've had the same results using the default Sprint DNS servers or using 4.2.2.2 thru 4.2.2.6. I've also experimented a bit the Link Drop Delay setting, but still had the same results.

I'll try the ipconfig /flushdns from the cmd line next time it happens, but it really seems more like a band-aid then a solution. Is this a bug in the CTR350 that should be reported to Cradlepoint??

muzicman82 · EVDO User Joined: 13 Dec 2005 Posts: 65

I'm not sure its a bug in the sense that they would accept... they obviously have a message page for it. The question is, what the heck does it mean? And, what causes it?

byrd · EVDO User Joined: 21 Dec 2007 Posts: 49

I should have mentioned... I have NEVER seen the message page that you are referring to. I simply loose my DNS settings.

The only way I eventually put 2 and 2 together, is that when I go to the WAN page and click on "Disconnect" then "Re-Connect" my DNS servers both get set to 0.0.0.0. The only way to get the DNS settings back correctly is to reboot the router, otherwise they are just stuck at 0.0.0.0.

Maybe I'm not waiting long enough for the message page to come up. How long does it usually take? Is it a pop-up? I've got pop-ups blocked. Whatever the case, the end results seem to be the same.

I've create a shortcut on my desktop for the ipconfig /flushdns. Now I just have to wait for the problem to show it's ugly face again... Confused

muzicman82 · EVDO User Joined: 13 Dec 2005 Posts: 65

It's instant just about. If my CTR350 is already on, I plug in my U720, and about 15 seconds later after it dials, if I try to go to a webpage, I get the CradlePoint message. I'll get a screenshot next time.

byrd · EVDO User Joined: 21 Dec 2007 Posts: 49

Maybe I don't see the message because I never actually remove my modem from the CTR350. I leave it in all the time and loose the DNS settings while the modem is actually plugged in. Just a guess...

jackrodgers · EVDO Addict Joined: 23 Mar 2006 Posts: 1131

Have you tried turning off the router rather than leaving it on and pulling the card? After you pull the card you may need to turn off the router before it works correctly.

I remember the proper procedure with my Comcast modem hooked to a netgear router:

Turn everything off, including the computer.
Turn on the modem and wait a bit.
Turn on the netgear router and wait a bit.
Turn on the computer.

When the steps were followed, no problem. Otherwise, problems.

My guess is that each device has its own memory and this memory persists until you turn it off. The on restart it re-initializes the memory.

jackrodgers · EVDO Addict Joined: 23 Mar 2006 Posts: 1131

Have you tried turning off the router rather than leaving it on and pulling the card? After you pull the card you may need to turn off the router before it works correctly.

I remember the proper procedure with my Comcast modem hooked to a netgear router:

Turn everything off, including the computer.
Turn on the modem and wait a bit.
Turn on the netgear router and wait a bit.
Turn on the computer.

When the steps were followed, no problem. Otherwise, problems.

My guess is that each device has its own memory and this memory persists until you turn it off. The on restart it re-initializes the memory.

My guess is that you need to turn off the router and the computer or else leave them on.