I can ping but not browse -- not a DNS problem

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Level 1

10 points

I can ping but not browse -- not a DNS problem

This only happens after I restart my MBP. The problem reliably lasts for several hours, then it clears up.

I can ping anything (using either the URL or the IP address).

However, if I browse or telnet the connection only works 1 out of every 20 or so attempts. When browsing for instance I can click reload reload reload reload .... until ... eventually a page might load (with or without pictures or css).

This started after I upgraded to Snow Leopard.

Can anyone give advice or help me isolate the problem?

MacBookPro5,3, Mac OS X (10.6.2)

Posted on Mar 18, 2010 5:54 PM

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Answer 1

adamgx Author

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10 points

Mar 18, 2010 5:55 PM in response to adamgx

By the way, if I go to my router's IP address, 192.168.1.1, it's the same problem.

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Answer 2

ctmurray

Level 1

88 points

Mar 18, 2010 7:37 PM in response to adamgx

There seems to be an issue with Snow Leopard and some wireless routers. Seems that Snow Leopard is "stricter" than previous versions about following the wireless standard, resulting in issues. These people often report a Leopard machine, or a Windows PC or even Windows running from a Mac will work, but the Snow Leopard machine will have issues like you describe.

http://reviews.cnet.com/8301-13727_7-10331876-263.html
A CNET article above.

Below some other discussions. One of them is very long and the CNET article covers many of the topics in the long discussion. No firm conclusion. Trying the various things works for some people, but no one thing or one type of router is to blame so far. But you can see people reporting success with some suggestions.

There is a long discussion of similar issues at a couple other threads:
http://discussions.apple.com/thread.jspa?threadID=2142725
http://discussions.apple.com/thread.jspa?threadID=2286188
http://discussions.apple.com/thread.jspa?threadID=2140025

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Answer 3

adamgx Author

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10 points

Mar 20, 2010 12:58 AM in response to ctmurray

Thanks for the tip but it happens when I use any network, including when I tether through my mobile.

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Answer 4

adamgx Author

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Mar 20, 2010 1:04 AM in response to adamgx

Just to be clear, my connection to my router is constant. I get 100% ping rate, at the same time I can not surf using any browser, except for the sporadic, seemingly random times I hit reload. I wondered if it had something to do with the packet size being bigger when browsing than when pinging. So I pinged with the largest packet ping allows, and that still works.

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Answer 5

roam

Level 6

13,637 points

Mar 20, 2010 2:38 AM in response to adamgx

Try opening your Application Firewall temporarily and see if that allows access.

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Answer 6

adamgx Author

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Mar 20, 2010 3:39 AM in response to roam

My Application Firewall was turned off. (I have Little Snitch installed). I turned Little Snitch off and AF on, but it didn't have an affect.

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Answer 7

roam

Level 6

13,637 points

Mar 20, 2010 3:52 AM in response to adamgx

So 'Allow all incoming' does not fix things? Little Snitch should be all right unless you have customised your browser in it.
The only other thing is to move your particular connection (airport?) to the top of the sidebar in Network dialog, to give it priority.
Apart from that, the poster ctmurray seems to have tracked a buginess about this in 10.6.

For what is is worth, you could submit this defect to,

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

Message was edited by: roam

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Answer 8

adamgx Author

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Mar 20, 2010 4:05 AM in response to roam

None of the three issues mentioned by ctmurry fitted my symptoms sadly. I guess I'm in a class of one.

The inconsistencies of the problem (after reboot, about 1 in 20 attempts to connect to a website works, and then after several hours after rebooting, all attempts work) seem to preclude it being a problem with any network or firewall settings. Def a bug somewhere. (Or hardware prob?)

BTW my Airport connection is at the top. I bought an USB wifi card to see if that helped, but it didn't, same problem connecting through it.

I feel like there should be some road I can go down to further diagnose the problem and isolate it, but not really sure where to begin. Any help appreciated.

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Answer 9

adamgx Author

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10 points

Mar 20, 2010 4:06 AM in response to adamgx

Would this be the kind of thing covered by warranty?

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Answer 10

Dogcow-Moof

Level 8

36,629 points

Mar 20, 2010 6:53 AM in response to adamgx

It doesn't sound like it's a warranty-related defect per se, but if you're still under warranty or AppleCare I'm sure the people at the Genius Bar of your local Apple Store or other Apple retailer (it doesn't look like Melbourne has an Apple Store of yet) would be happy to help you out.

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Answer 11

Mar 20, 2010 10:14 AM in response to adamgx

Hi adamgx.
I have exactly the same problem.
ping works in local network (ethernet 100 mbps) and to Internet hosts, dns requests works (tested with nslookup) but telenting google for example gives em timeout. I checked connection status with netstat and looks like the TCP conection does not receive the SYN ACK from the host i try to connect to. Therefore the connection timeouts after being there in SYN_SENT state for about 1 minute and 15 seconds.
I checked my ethernet cable and also uncplugged it to test this issue with connected via wireless (WPA2-PSK).
I have a windows xp sp2 machine too that has access to LAN and internet using the same ethernet cable and/or wireless connection used during testing.
I can´t reach (connect to) a Apache web server running in the same subnet.
Routing is not an issue. Default route is set up to router´s ip.

Logs doesn't show useful information about this issue.

Looks like a MacOSX 1.5.8 networking module issue to me.

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Answer 12

adamgx Author

Level 1

10 points

Mar 20, 2010 11:18 PM in response to humberaquino

hi humberaquino

so yours starts to work properly after several hours like mine, or never works?

I'm on 10.6.2 btw

cheers, adam

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Answer 13

Mar 21, 2010 7:57 PM in response to adamgx

Actually, I did all tests in about an hour. After that I turned off my Mac.
I´ll leave it on all day tomorrow and let you know if it behaves the same way.

Best regards

Humber

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Answer 14

Mar 22, 2010 7:46 AM in response to humberaquino

Hello adamgx,

I know what was my problem. It's a firewall misconfiguration, mostly my fault.
noobproof ( http://www.hanynet.com/noobproof/) configured MacOSX's firewall to deny incomming TCP traffic, and when I tried to allow traffic (Allow all incomming connections) from Default Firewall configuration panel the rules where continue active.
I solved it giving default configuration to the firewall using noobproof and now networking is good again.
You should enable Firewall debug (Security -> Firewall -> Set Access to specific... -> Advanced -> Enable Firewall logging) and then click on Allow all incoming connections.
After that take a loot at /var/log/appfirewall.log to see if there're some Deny TCP logs.
You can check current rules using the following command: sudo ipfw list
My current output is:
65535 allow ip from any to any

Which allows pretty much everything.

Let me know if this works for you too.

Cheers

Humber

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Answer 15

Mar 22, 2010 12:31 PM in response to adamgx

I'm having this problem as well. 10.6.2. Ethernet works, wifi has trouble getting an IP address and then when it does, no web applications EXCEPT for Ping work. no firewall, deleted wifi .pref's, reset the System Management Controller (SMC), added annd removed the airport, repaired permissions, hard-reset router. My husband's mac book pro works fine via wifi on the same network. I'm stumped..

To recap, its not:
1. the routert
2. the dns
3. network preferences
4. file permissions
5. firewall
6. SMC

Furthermore, no changes were made prior to the problem -- it just Stopped Working.

Help?!

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