DHCP lease not renewing

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DHCP lease not renewing

Hi all,

I currently have an Airport Extreme base station 5th generation in a small office setting. I am required by one of my software vendors to have a static IP address and port forwarding enabled. Recently, I have had several pieces of equipment lose their connection to the router. I have completely reset the router, recreated the configuration from scratch (not imported), have even had Apple replace the base station so it's unlikely it's a hardware issue. I have also tried reverting the firmware to 7.6.1 as I thought I may have updated to 7.6.3 shortly before this all happened but still no luck. I have had my ISP verify all the modem settings were correct.

I have a computer with Airport Utility 5.6 on it so I was able to do a little more digging and in the advanced tab under DHCP clients, I noticed that several clients had leases that expired in 1953 but were not renewing. I would reset the router (disconnect and reconnect power) and all would be good for a day or two and then it would happen again. I have tried adjusting the DHCP range and lease time with no luck either. I have talked to Apple support multiple times and have verified all the settings and have been told everything should be working. I am completely stumped. Apple support did indicate that it may have something to do with the static ip configuration as that's not a fully supported feature but it's beeng working fine for over a year now with no problems. As I can best recall, nothing changed right before the problem developed so I am at a loss of what further troubleshooting steps to take.

Has anyone seen or had a problem like this? Any sugestions?

Any help would be greatly appreciated.

Thanks!

Airport Extreme-OTHER, Mac OS X (10.7.5)

Posted on Aug 19, 2013 11:26 AM

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Answer 1

John Galt

Level 10

155,798 points

Aug 19, 2013 11:57 AM in response to ibraces

Hi ibraces

I have also tried reverting the firmware to 7.6.1 as I thought I may have updated to 7.6.3

This is likely to be a minor point but newer firmware is now available: http://support.apple.com/kb/DL1673

Launch the current AirPort Utility version to download it and update the Extreme.

Another minor point is that although you can use AirPort Utility 5.6 to examine the logs (there is no other way to do so) I suggest that you do not use AU 5.6 to actually write and update any 802.11n AirPort Extreme settings. I have no proof, only anecdotal evidence that using 5.6 to write parameters to an 802.11n Extreme may interfere with its normal operation. I have been testing this hypothesis over several months and have no conclusive results to report, but just be aware of that possibility. Use AirPort Utilty 6.3.1 to write all configuration settings, and if you used an earlier version in the past it may be wise to "hard reset" it and reconfigure it using AirPort Utility 6.3.1 out of an abundance of caution.

As for the DHCP leases showing preposterous expiration dates, make sure all the clients are using an Internet time server to keep their real time clocks synchronized. I have no other explanation.

A static IP address is not an unusual application and I am very skeptical of Apple's suggestion that it is not a fully supported feature. An AirPort Extreme doesn't care what IP address is issued or assigned to it.

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Answer 2

Bob Timmons

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185,042 points

Aug 19, 2013 11:59 AM in response to ibraces

I am required by one of my software vendors to have a static IP address and port forwarding enabled.

The Static IP is self explanatory, but the "port forwarding enabled" requirement is not.

Your vendor may be looking for UPnP Port Forwarding....which Apple does not directly support. Instead, Apple uses NAT-PMP, a workaround of sorts, which requires that ports be manually configured. That usually will work, unless there are new port forwarding requests coming down the line, which would require more manual configuration.

Can you get some clarification for us on whether the vendor needs full UPnP support?

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Answer 3

ibraces Author

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Aug 19, 2013 1:02 PM in response to John Galt

Thanks! I updated to 7.6.4 so perhaps that will resolve the issue.

I'll check as many clients as I can for where they are getting their time from but I have a few things like networked printers, scanners, and even an eye-fi card that I don't know if that's even an option. I figured something has to be broadcasting that date but I'm surprised that, if it's not the modem, that the AXB would respond to it.

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Answer 4

ibraces Author

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Aug 19, 2013 1:03 PM in response to Bob Timmons

Thanks Bob!

I checked with the vendor's support and they said they do not need full UPnP support. I just put in the IP address of the server point those ports to it. Sorry if I am not using the correct terminology. I'm not well educated in networking.

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Answer 5

ibraces Author

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Aug 20, 2013 6:54 PM in response to ibraces

Update - Using Airport Utility 5.6, I caught an entry in the log. Last normal entry was today at 2:30 pm. The next entry in the log is:

Dec 07 16:54:57

Severity:5

Clock synchronized to network time server time.apple.com (adjusted -1884026061 seconds).

And now, leases are showing expirations for 1953 again.

Any ideas what could be causing this or how to work around it?

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Answer 6

John Galt

Level 10

155,798 points

Aug 20, 2013 8:59 PM in response to ibraces

1,884,026,061 seconds ago was December 7, 1953. The reason Apple's network time server decided to make such a bizarre adjustment is a mystery, but would explain your equally bizarre DHCP lease expiration dates.

Unfortunately I haven't the slightest idea how that can occur. AirPort Utility 6 removed the option of choosing a different time server so that's out, and I am reluctant to recommend using AU 5.6 to change it for the reasons I explained earlier.

I suspect the problem may lie with your ISP. Are you using specific DNS addresses, or the defaults chosen by your ISP?

Buy a UPS for the Extreme to rule out momentary power interruptions. Bizarre problems such as this may be explained by poor power quality causing erroneous data to be communicated or stored in the Extreme. The cause is likely to be something simpler than that but a UPS is a good idea, especially for an office. A quality UPS of sufficient capacity for the Extreme plus some modest networking equipment will cost less than $50.

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Answer 7

ibraces Author

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Aug 21, 2013 6:26 PM in response to John Galt

Thanks John!

I have contacted the ISP again and they didn't find anything wrong but are escalating. I am using specific DNS addresses provided by the ISP.

I have had all my equipment on a UPS since installation. 🙂

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Answer 8

R C-R

Level 6

17,794 points

Aug 22, 2013 5:36 AM in response to ibraces

Have you checked the modem's logs for any clues?

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Answer 9

John Galt

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155,798 points

Aug 22, 2013 12:51 PM in response to ibraces

Out of curiosity try the following:

Open Network Utility - it is in your Mac's Utilities folder. Select Utilities from the Finder's Go menu to open it and launch Network Utility.

In the Lookup tab, what are the results of looking up the address time.apple.com?

Compare yours to mine:

Copy and paste the text or post a screenshot of your results.

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Answer 10

ibraces Author

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Aug 22, 2013 1:10 PM in response to R C-R

I tried finding the Modem's logs but after looking through all the menus, couldn't find anything. ISP is Comcast and it's an Arris modem. I googled how to view the log files but I'm getting too many results for "log in", not log. Any tips on how to find it?

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Answer 11

ibraces Author

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Aug 22, 2013 1:14 PM in response to John Galt

Tried the lookup, good tip but I don't see anything out of the ordinary. Do you?

I thought I was out of the woods because the time updated last night without incident.

Aug 21 18:11:06

Severity:5

Clock synchronized to network time server time.apple.com (adjusted +0 seconds).

But then I came in this morning to another round of fun...

Aug 22 07:11:03	Severity:5	Rotated CCMP group key.
Dec 07 16:54:57	Severity:5	Clock synchronized to network time server time.apple.com (adjusted -1884172574 seconds).

Thanks everyone for all your help. I really appreciate it.

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Answer 12

John Galt

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155,798 points

Aug 22, 2013 1:50 PM in response to ibraces

ibraces wrote:

Tried the lookup, good tip but I don't see anything out of the ordinary. Do you?

No 😟 but is there any additional output after the last line in your screenshot? Scroll all the way to the end.

It's interesting that time.apple.com is not making the same adjustment (delta). It is specifically issuing the exact same time (Dec 7, 1953, 16:54:57) again and again. As in Groundhog Day. Are you waking up to "I've got you babe"?

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Answer 13

Aug 22, 2013 2:36 PM in response to ibraces

Are your systems (the Mac ones at least) syncing their time from time.apple.com also? No problems with them I suppose. Anything in the system console logs concerning time syncing? I know this is happening on the APEx but still it might be worth a look.

You are located in the states right? A huge coincidence but Dec 7 is student day in Iran. In 1953 3 students were killed in a protest. No chance someone is trying to make a statement?

Crazy I know but nothing with your problem seems to be making any sense. If Apple had a time server doing this I would imagine a lot more people would be seeing it and complaining.

good luck

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Answer 14

ibraces Author

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Aug 22, 2013 3:17 PM in response to John Galt

Sorry. The first one I posted was from OS X 10.5. Looks like the network utility for that version is slightly different. Here's a more current one:

LOL. Yes, it is Groundhog Day-esque... No Cher in the background though. I did notice that it kept resetting to the same date and time but I am at a loss to explain how or why.

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Answer 15

ibraces Author

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Aug 22, 2013 3:23 PM in response to Frank Caggiano

Frank,

Yes, other systems syncing with no problem.

I checked the console logs on a couple of systems and didn't see anything.

Yes, located in the states. I was wondering if the date was significant but when I googled it, nothing came up. Once I noticed it was the same date and time over and over again, the thought that someone was trying to make a point occurred to me. But as you pointed out, this should be more widespread. Makes absolutley no sense.

I think my next steps are to put a packet sniffer on the network and review network traffic the next time it happens. I might also try putting the router in bridge mode and using the modem as a router instead. This is really frustrating since it's starting to consume a lot of time and has become very annoying but the cause continues to ellude and the troubleshooting is getting more and more elaborate. Ugh...

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