Airport TC internal dns not responding

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Level 1

10 points

Airport TC internal dns not responding

I'm looking into a problem with an airport Time Capsule that randomly seems to stop responding to dns queries. All of the systems on the LAN are functioning both wi-fi and hard wired however randomly they can no longer connect to the internet and upon investigation I have discovered that the dns server inside the airport router is no longer responding.

From a system on the LAN when internet connectivity is lost, I performed "nslookup google.com" and this simply times out, but if I perform "nslookup google.com 8.8.8.8", then I get a valid response, suggesting that there is something wrong with the dns server in the airport TC.

Rebooting the Airport TC resolves the problem, until the next hang, which could be minutes or day later. I have performed a hard reset and restored the configuration and am waiting to see if this will help.

I should mention that this configuration has been install and working (to the best on my knowledge) for about 1 year and I'm not aware of any recent changes that might have introduced this issue.

Has anyone else observed this problem and know of a solution?

Airport Time Capsule-OTHER, Other OS, Airport Time Capsule

Posted on Dec 18, 2015 6:32 AM

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Answer 1

Dec 18, 2015 11:39 AM in response to NathonC

DNS has become extremely problematic. But your issue might be the Mac and not the TC.

Yosemite has serious DNS bug in the networking application.. here is the lets say more arcane method of fixing it by doing a network transplant from mavericks.

http://arstechnica.com/apple/2015/01/why-dns-in-os-x-10-10-is-broken-and-what-yo u-can-do-to-fix-it/

Watch out for domain issues.

Do a netstat scan from the network utility and check domains.

For instance I cannot ping my TC by name unless I add the domain.

I should mention that this configuration has been install and working (to the best on my knowledge) for about 1 year and I'm not aware of any recent changes that might have introduced this issue.

Did you install El Crapo on your computer though?? What OS are you running?

I presume this is the latest AC version TC.. if not tell us which one and which firmware?

Give us a whole network setup because there are definitely issues with the latest airports and some modems.. SB6141 being top of the list.

A few screenshots from airport utility of the configuration can also help.

I have a setup where I run into the same issues..

I have no issues with the older Gen4 TC.. but the newer Gen5 disappears occasionally. It is just not that stable.

Do watch out for antivirus software. If you install anything like that on your computer expect trouble.

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Answer 2

NathonC Author

Level 1

10 points

Dec 19, 2015 8:02 AM in response to LaPastenague

Thanks for the response, this network belongs to one of my children who engages me for system/network issues because of my 30+ years of experience in enterprise systems and networking with large scale data centers, also obtaining screenshots is not so simple.

The LAN contains an variety of systems, mac, ipad, iphone, windows, Linux, android and a several other platforms with imbedded systems.

All of thenm that I have looked at suffer the same connectivity problem, so I suspect it is not OS-X related and as far as that goes, there is a combination of Yosemite & Mavericks too, no El Capitan involved.

The TC is the latest version at fw 7.7.3 and is connected to a COX cable network, which I have eliminated by replacing the original Cisco DPP3010 cable modem, with an older Cisco CM100 (DOCSIS 2.0) cable modem, then a Motorola SB6183 cable modem and still experience the same issue.

Because screen shots are not available right now:

Inet <--> Cable modem (SB6183) <--> Airport TC <-|

| ---------> Airport TC #2 in bridge mode to extend Wi-Fi to other end of building

| ---------> Dlink 24x1GbE switch for hard wired systems.

From memory I can tell you that when I have looked at this issue, the Airport utility indicates that the internet is "disconnected", but still lists the external IP Address and both of the ISP provided DNS servers.

Most of the internal systems are configured for DHCP and using the TC base unit as the DHCP server.

Looking at the DNS server list on one of the mac's (Mavericks) I only see the TC base using 10.0.0.1, if I manually replace the DHCP provided DNS address with either of the COX provided DNS servers, or the public Google server 8.8.8.8 via the network configuration GUI, then everything works.

When I concatenate the public DNS server address to 10.0.0.1 address, then nslookup works, but it is evident that the request has to time-out on the first TC based DNS server, before going to the external server.

Hope this helps.

I would love to be able to obtain logs from the TC, but all indications are that this is not possible.

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Answer 3

Dec 19, 2015 12:31 PM in response to NathonC

Thanks for loads more background info.

You are one of several people who has the background knowledge to realise the airport router (and particularly the new series) are just not working very well. (Funny in the last week I have come across this a few times in different routers where the local DNS was causing major network issues).

My strong recommendation is to get a replacement router. (not apple).

Since there are such limited controls with the apple routers there is so little you can do to fix it.

I personally run a router (cheap end TP-Link) on gargoyle (a modified OPENWRT). I was forced to do this long ago because Apple routers have a poor implementation of PPPOE, which I require for my adsl broadband. So I have no choice.

I do however run the TC and several other apple routers at various time.. (I repair the TC and wrote up that info)

So I use a main apple router set to static IP mode and dhcp.

Re: airport time capsule keeps disconnecting

I found this worked better than bridge.. which also was failing.. However I also note it is not perfect .. the advantage of this from DNS point of view is that in static IP mode the TC passes the DNS addresses you set on the Internet tab to the clients. Not itself.

So my current setup looks like this.

On a computer connected by ethernet.. (or wireless) I get the IP via the TC.. but the DNS servers are those listed on the WAN setup.

I can see what is going on by using a version 5 airport utility. This is possible to load into later versions of OSX using a script easily found on the internet.. just lookup 5.6.1 yosemite .. Apple deletes my posts if I give the reference..

Of course if you have access to windows PC you can load the v5 for windows. It will give you the same results.. it will state it is unsuitable for the AC model but will work fine to get info.

So why not scrap the apple router.. well I do find the apple stuff runs well with it.

I have plenty of other routers that people can connect to .. although I notice with the house full of relatives for Christmas.. I have a heap of android phone.

In a setup like yours I would use the apple router (In AP mode of some sort) for apple products and simply use another brand for the rest if you are having issues.. with the main router using a solid firmware where DNS is not going to go astray.

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Answer 4

NathonC Author

Level 1

10 points

Dec 19, 2015 6:25 PM in response to LaPastenague

Do you happen to know how to get the engineering folks at Apple to assist in providing an engineered solution to this issue, rather than throwing money at it?

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Answer 5

Dec 19, 2015 8:05 PM in response to NathonC

If you have applecare you can ring support.. outside of 30day initial purchase and no apple care they will charge you and will actually not be able to help.

You can also submit a feedback report.

http://www.apple.com/feedback/timecapsule.html

Since no firmware has been released since 7.7.3 and that was only a security patch.

AirPort Base Station Firmware Update 7.7.3 - Apple Support

So the last real effort at firmware was 7.7.1 on the day of release of the AC models as I remember which is July 2013 and 7.7.2 which was removed due to the security flaw was Nov 2013.

http://www.macrumors.com/2013/11/21/apple-releases-airport-extreme-and-time-caps ule-firmware-update-7-7-2/

So Apple have done nothing for over two years..

I cannot see them fixing DNS issue any day now.. !!

rather than throwing money at it?

The recommended TP-Link router.. is <$50.

http://www.amazon.com/TP-LINK-TL-WR1043ND-Wireless-Detachable-Antennas/dp/B002YL AUU8

It is closer to throwing small change at it.

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