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larkw Author

Level 1

0 points

Mavericks network issue

Since I upgraded my MBA late 2010 from 10.6 to Mavericks, random network "unreachable" happens now and then. When the "unreachable" happens, the WIFI keeps connected, but applications can't connect to outside (there are exceptions, see below). The only cure is turn WIFI off and on. The randomness is timing: you may use it w/o problem for hours, then you keeps encountering problem within minutes time frame after turning WIFI off and on.

At first, I think it is buggy WIFI driver or WIFI device incompatibility (though WIFI works without any problem before upgrade). I spent a lot of time to find the real reason, and now it seems that some OS mechanism kicks in when problem shows off.

I have MBA (192.168.0.100), a router box (192.168.0.254) and server box (192.168.0.250). Router box runs dns, ssh, nginx and acts as NAT gateway.

1. keep a 'ping 192.168.0.254' in MBA's terminal

2. keep ssh connection to 192.168.0.254 and 192.168.0.250 from MBA (maybe run 'top' or other program which output continuously)

I use firefox, chrome and safari to browse internet. When I see browser shows "looking up" or "connecting" but freezes there, one of the following is true:

1. ping shows "Request timeout for icmp_seq XXX"

2. ping shows "64 bytes from 192.168.0.254: icmp_seq=XXX ttl=64 time=??? ms"

Sometimes(i.e, not always), these are true:

1. both 'telnet 192.168.0.254 22' and 'telnet 192.168.0.250 22' can't connect

2. both ssh connections work fine: I can type and get feedback or watch 'top' running and refreshing in ssh session

3. I can log out both ssh connection and re-login without problem

4. dns queries freeze

5. 'ping 192.168.0.250' timeout

6. 'telnet 192.168.0.254 22', then run tcpdump on both MBA and router, I can see it's packets (syn packet) sent out in MBA's end but no packet received in router's end. The unusual thing is TCP retries never end

7. 'ping 192.168.0.100' from 192.168.0.254 works fine

PUT IT SIMPLE: when network is unreachable, sometimes existing tcp connections still work, and ping randomly works or not; no clues about why this happens.

And the firewall on MBA is always turned off.

After this OS upgrade, this MBA is very hard to use. I don't know OS X much, and usually this MBA is used by my wife and she just do some web surfing. I had to spend a lot of time to try to resolve this problem.

Any help is welcome. If any furthur information is needed, feel free to ask.

T.I.A

MacBook Air

Posted on Nov 17, 2013 8:53 AM

25 replies

etresoft

Level 9

51,016 points

Dec 19, 2013 7:48 AM in response to Magnetics

Then you need to start your own thread and describe your problem and setup. Invariably, people who respond with "me too" and "I have the exact same problem" have a completely different situation. The last place you want your problem addressed is in someone else's rant thread. The more specifics you can provide, the better. That will also keep your thread from devolving into a rant thread and taken over by others with different problems.

Dec 19, 2013 8:21 AM in response to etresoft

etresoft wrote:

Then you need to start your own thread and describe your problem and setup. Invariably, people who respond with "me too" and "I have the exact same problem" have a completely different situation. The last place you want your problem addressed is in someone else's rant thread. The more specifics you can provide, the better. That will also keep your thread from devolving into a rant thread and taken over by others with different problems.

I thought about it, but I honestly don't think there is a solution for me outside of an OSX network utility update/patch since all devices outside of my computer are up to date and appear to be working properly. I have read through a number of Network Issue discussions (almost all with no solution) and I chose to post in this thread because it was close to the basic issues I was experienceing (10.6 to 10.9 upgrade, unreachable network/disconnects). The only change for me was the OS upgrade. Prior to that everything worked. My goal in posting here was just to add a little credence to the idea that there is possibly a Networking issue in Mavericks.

Dec 20, 2013 10:36 AM in response to larkw

A colleague recommended the instructions on this page: http://blogs.citrix.com/2013/10/31/citrix-on-osx-10-9-mavericks/

Even though my issue has nothing to do with Citrix, I tried this and my VPN connection using Juniper Network Connect has been stable now for almost 4 hours, and that hasn't happened since I upgraded to Mavericks. If you don't want to go to that page, the instructions are:

sudo su
touch /etc/sysctl.conf
echo net.link.ether.inet.arp_unicast_lim=0 >> /etc/sysctl.conf
chown root:wheel /etc/sysctl.conf
chmod 0644 /etc/sysctl.conf

and then reboot.

Dec 26, 2013 11:39 AM in response to larkw

Unfortunately, I have to reply with a "me too". I have been diagnosing this problem for weeks. I have a feeling that this is a Maverick issue.

I have a web application that sends a POST request to a backend every second. It recently starts to fail because occasionally some of the POST request would fail. I have made the following observations:

It is reproducible on OSX 10.9 and OSX 10.9.1 on all browsers
It is not reproduciable on OSX 10.8, Windows, and Linux running on the same network, wired and wireless.
The failure happens on the client side. The XDR request simply cannot reach the host in one second, and in the following second, it is fine again.
Problem does not happen on localhost -- only to external host (in my case EC2). Again, Windows, Linux, and OSX 10.8 have no problem.
I am able to reproduce this using direct IP address (to verify it is not DNS issue), and with/without IPv6

I am not sure how this is would be a router issue when it appears that this problem does not happen on other platforms, and other versions of OSX.

Dec 26, 2013 11:58 AM in response to tmueller64

Unfortunately, this change to the ARP unicast setting did NOT fix the problem. After a few days, the symptoms returned.

etresoft

Level 9

51,016 points

Dec 26, 2013 12:00 PM in response to rickfromlos altos

rickfromlos altos wrote:

Unfortunately, I have to reply with a "me too". I have been diagnosing this problem for weeks.

Indeed it is unforunate. You have been having a problem for weeks and you report it in one of the few places on Apple Support Communities where you are guaranteed to have it ignored for weeks again.

Who do you want to read your post? Other people with networking problems who have decided to blame it on Mavericks? Or people who know networking?

I have a web application that sends a POST request to a backend every sec

I've read enough. Fix your web application. It is hopelessly broken. Different machines, browsers, OS versions, networks, all have different interactions with all of the different parts of the internet. I would expect such a web application to fail on a regular basis. What you call a Mavericks bug sounds to me like Mountain Lion bugs that have been fixed.

The internet is not reliable enough for HTTP requests once per second. Various OS vendors, especially Windows and Linux, try hard to hide such errors from the user. They are probably using more aggressive caching mechanisms to fake out your application. Windows, for example, requires a special, dummy parameter on each request to make it unique. Otherwise, it won't even bother sending it. Linux is always a different story because each Linux machine is unique.

Dec 26, 2013 1:29 PM in response to tmueller64

Thanks a lot for sharing. This solves my problem.

Troed

Level 1

0 points

Mar 17, 2014 8:16 AM in response to larkw

I have this exact problem. Since a few weeks back (which makes me doubt it was in 1.9.0, but maybe I was lucky) my mid 2009 Macbook Pro suddenly and regularly has its networking slow to a crawl, including completely stopping. It can either be waited out, or "fixed" temporarily by switching networking off/on or restarting.

It happens to the IP or TCP layer (haven't checked UDP) and it also happens to existing network connections. I always have a VNC session to another Mac on my local network active and thus I can be perfectly sure the symptom has nothing to do with routing (Airport Extreme), DNS lookups, general Internet connectivity or a specific protocol.

The problem can appear several times in a few hours, or more seldom. The low networking speed, before timing out completely, can be verified in the activity monitor.

/Troed

kreddy81

Level 1

0 points

Apr 5, 2014 1:31 PM in response to larkw

had this issue where my macbook pro and imac were able to connect to the internet but couldnt see each other on the wireless network.

In order to solve this i logged into my wireless router went to "LAN Administration" and added a static route to both my macbook and imac..

lets say u have 2 computers and these are their ip addresses: ( you can get these stats from system preferences 'network' - wifi - advanced - tcpip)

apple1 - 192.168.1.5

subnet mask - 255.255.255.0

gateway - 192.168.1.1

apple2 - 192.168.1.6

subnet mask - 255.255.255.0

gateway - 192.168.1.1

so in my router i would add the static route like so:

IP=192.168.1.5 Mask=255.255.255.0 Gateway=192.168.1.1 metric=1 interfacetype = LAN

IP=192.168.1.6 Mask=255.255.255.0 Gateway=192.168.1.1 metric=1 interfacetype = LAN

now both my computers can see each other and share files.

Dec 9, 2014 4:33 AM in response to tmueller64

That did it for me as well. I'm relieved there is finally a fix for this. More background info on this bug can be found on these pages:

Different thread describing the problem and the solution:Mavericks and Failed ARP causing network drops!
Detailed description of the underlying problem and fix: http://www.macstadium.com/blog/osx-10-9-mavericks-bugs/
Related question on StackExchange with some diagnostics and my answer directing to the two links above: http://apple.stackexchange.com/a/160020/99523

Mavericks network issue