Accessing only SOME urls in wireless

barenare
barenare used Ask the Experts™
on
Have previously been using several LINKSYS wireless products without difficulty - on a cable modem (Toshiba)/Time Warner cable modem.  Yesterday I encountered difficulty accessing only some (many) websites - (they cannot be reached by browser and result in time-out error by ping)  For examply i can access google.com and msn.com but not microsoft.com or linksys.com.  I have cleared the internet cache. I can access the internet completely fine with a wired connection.  

I am using Linksys:
BEFW11S4
WCP11 ver 3
Windows XP on one machine (wired/wireless)

Their Tech Support agent worked several config changes, suggested contact cable company and find out correct MTU value, but finally attributed the problem to interference - BUT it persists when all phones (cordles/cell) are disconected, at different times of day, and with different proximities from the router (5 to 50 feet)  I have excellent signal strength at all times, and believe it is not due to interference.

The setup was working fine a day earlier and I have not (by intent) changed any software configuration.
I have searched and cannot find a clue to the solution.

Do you have any recommendations?
Thanks for your assistance.
Comment
Watch Question

Do more with

Expert Office
EXPERT OFFICE® is a registered trademark of EXPERTS EXCHANGE®
Unfortunately, I have timewarner cable also (which is why I also have another connection to the home) and we see this sort of thing all the time.. to this day, if i am using only the cablemodem, I cannot get to jcwhitney.com


Has been happening for me for over a year. -- Timewarner is the culprit.

Author

Commented:
US dot net,
does this happen wired as well as wireless?
I dont see why wireless versus wired should really matter.. the connection media is not your designater as to wether an ip address is reachable, the router is modem isn't reaching the IP, not the handheld PDA, or the wireless laptop, opr whatever.. if you said "i cant reach any sites with my wireless computer" then I'd say your wirelss network card, or your router were the culprit.. but the ROUTER is what actually visits websites, not your computer (in real laymens terms) the router just passes to you whatever information it receives


Ensure you’re charging the right price for your IT

Do you wonder if your IT business is truly profitable or if you should raise your prices? Learn how to calculate your overhead burden using our free interactive tool and use it to determine the right price for your IT services. Start calculating Now!

Commented:
When you are comparing wired to wireless, are you talking about the same machine over the same cable connection to the internet or are we talking different machines at different locations?

Author

Commented:
Wired = laptop PC with wireless card OUT with wire connection to cable modem...CAN access internet fully

Wireless= SAMe laptop with PC card in and cable disconnected only able to ping certain urls!

Author

Commented:
also contaced Time Warner and they indicate they do not require any specific MTU setting (and of course they dont provide tech support for a wireless broadband connection)

Commented:
What is your MTU across the wireless link?  Is it smaller than 1500?  If so, is the wireless router configured to send ICMP messages to source machines that set the DF bit?  Also if it is smaller than 1500, have you tried raising it to 1500 to see if it starts working?

Author

Commented:
The default LINKSYS router setting is DISABLE MTU.
I have tried setting to 1294 without success.
Will try setting above 1500.
Do not know about ICMP config. (yet).

Commented:
Rather than setting it above 1500, I would try it AT 1500.

Author

Commented:
MTU is automatically set to 1500 when DISABLE is chosen on the LINKSYS

Author

Commented:
MTU is automatically set to 1500 when DISABLE is chosen on the LINKSYS

Commented:
Just to clarify - is that "disable" setting universal on the device or just for the outside (cable) connection?  Is it possible the wireless segment is using a smaller MTU?

I'm not trying to hammer on this, but a smaller MTU can be a primary cause of a situation where certain sites can't be hit - especially when the only difference is the physical segment.  

I am assuming it is consistent which sites work and which sites dont?  In other words, certain sites ALWAYS fail, while others ALWAYS work - or is it more sporadic?

Author

Commented:
I think it is universal - there is no indication otherwise.

It also appears the sites which fail are consistent - though i want to check this again later today.

the weird think is it workd fine a day ago - the only difference is I upgraded MSNMessenger - and the wireless worked fine after two subsequent unrelated power off/re-boot cycles.

I am wondering if i should upgrade the firmware for the router/card.  Or just start over in a new congig which will calso include a PC with wireless card (that is also cable distance from the router - just in case!)

Commented:
Is there anything in between the modem and the router or is it just a cross-over?  It would be interesting to get a sniffer in there and see what traffic you are getting in both directions to see if you can pinpoint whether the failure is on the outbound request, the inbound reply, or something else.

Author

Commented:
no there is nothin between the router and modem cept cat5
AND the websites are NOT consistent - the failure rate is less today - but still present

Commented:
Hmm, yeah if there is no consistency then it probably is more of a transmission failure issue.  What happens if you bring the laptop really close to the router?
well, since it's random , then its the fact that your running wireless.. (yet another reason I have yet to embrace it, it's as high quality as cellphone)


Your just getting data errors.
I am using the exact same router and have time warner RR internet access, but I have not yet seen any of the problems you are describing.

When you have the wireless card in, start up a DOS prompt and do a route print, see if the routing tables make sense.

I would also double check your DNS settings under the wireless card.  If your addresses are dished out by the router via dhcp, try statically assigning them completely (gateway, dns, ip, etc)  or if they are statically assigned, try letting them pull dhcp from the router

Les MooreSr. Systems Engineer
Top Expert 2008

Commented:
If you have Firmware Version 1.42.7, you need to upgrade to 1.43 on your LinkSys router. The shipping code is broke in many ways.
Les MooreSr. Systems Engineer
Top Expert 2008

Commented:

How are things going? Did you get the help you need? Can you provide some feedback?
Les MooreSr. Systems Engineer
Top Expert 2008

Commented:
barenare
No comment has been added lately (103 days), so it's time to clean up this TA.
I will leave a recommendation in the Cleanup topic area for this question:

RECOMMENDATION: PAQ question

Experts, please leave any comments here within 7 days.

-----------------------------------------------------------------------------------
PLEASE DO NOT ACCEPT THIS COMMENT AS AN ANSWER!
-----------------------------------------------------------------------------------

Thanks,

lrmoore
EE Cleanup Volunteer
---------------------
If you feel that your question was not properly addressed, or that none of the comments received were appropriate answers, please post
comments here

Commented:
Finalized as proposed

modulo

Community Support Moderator
Experts Exchange

Commented:
I'm not an expert but I've run into othis problem also and I've found that RR's DNS is sometimes corrupt.

I now use a DNS server on my own webhost to resolve addresses instead of using the ones provided by Road Runner.

Do more with

Expert Office
Submit tech questions to Ask the Experts™ at any time to receive solutions, advice, and new ideas from leading industry professionals.

Start 7-Day Free Trial