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The Graveyard - Products No Longer Supported => Routers / COVR => DIR-655 => Topic started by: fgl30 on March 12, 2008, 10:40:08 AM

Title: Possible bug discovered?
Post by: fgl30 on March 12, 2008, 10:40:08 AM
I use DIR-655 in DHCP mode, without making reservation for any connected devide.

Well, time to time I have a terrible problem: I open a web page, and Firefox give error message, and donŽt load page. I push "try again" one, two or more times and page load. I always blame my ISP for that, and never tested this really hard isolating router... today I made some test: I fixed an IP in my wired network card and after that it seems problem doesnŽt appear any more... could really be a router DHCP fault? If yes, why this happens with wireless devices too?
Title: Re: Possible bug discovered?
Post by: AWDL on March 12, 2008, 01:35:22 PM
Anybody else have this problem?

fgl30,

What is the frequency of your problem?

I only have one PC set-up with wired connection DHCP (not reserved). I primarily use Firefox (2.0.0.12) on it (winXP pro SP2, TimeWarner) and I haven't seen that problem.
Title: Re: Possible bug discovered?
Post by: fgl30 on March 12, 2008, 04:58:25 PM
well, is a really strange problem... frequency is difficult to determine... some times per week... and it happens with wireless device too...
Title: Re: Possible bug discovered?
Post by: TaVARUS on March 13, 2008, 03:42:28 PM
Hi Fgl30,

    I've not heard of the specific problem your describing, can you nail down some details for us? When you said, you have seen it on wireless too, what OS were you running on that PC? Please give DIR-655 hardware and Firmware currently running. I am really tyring to see if it is OS & Firmware specific/combination there of.

    I would request you to change the Lease time on the DHCP offers, then, comment back if problem is only occurring  with that loss of IP (due to DHCP Lease expiration) and then your sporadically not getting and Offer/IP back. This is not a wide spread epidemic with the DIR-655; just specific to your network at this time. Also, if you have upgraded your firmware and had not noticed this problem before, I would have you clear the router of any previous configuration (Reset to Factory Defaults) see if the problem still exists. If you have the time to do so, please let us know the outcome?
Title: Re: Possible bug discovered?
Post by: spinn on March 15, 2008, 10:04:42 PM
How is your network setup?  workgroup or domain, almost sounds like the dns server is not being located immediately
Title: Re: Possible bug discovered?
Post by: fgl30 on March 21, 2008, 04:47:02 PM
workgroup....
Title: Re: Possible bug discovered?
Post by: TaVARUS on March 24, 2008, 08:35:53 AM
The next time this problem occurs, see what you can PING. Let us known what your able to Ping? If your able to PING IP Address on the Internet, but not FDQN (ie. google.com or yahoo.com); then it's a DNS resolution problem! If so, and your not using "Web filter" feature, then you can Disable DNS Relay (SETUP tab>> NETWORK SETTING page >> Enable DNS Relay option).
Title: Re: Possible bug discovered?
Post by: fgl30 on March 24, 2008, 10:17:51 AM
Thx. IŽll try and let you know.
Title: Re: Possible bug discovered?
Post by: Lycan on March 24, 2008, 02:07:11 PM
What virus software / Firewalls are you running on that machine?
Title: Re: Possible bug discovered?
Post by: fgl30 on March 24, 2008, 02:54:24 PM
@TaVARUS: not worked :'(  In fact, if I disable DNS relay I canŽt connect to internet

@Lycan: I use AVG Free edition + winxp firewall
Title: Re: Possible bug discovered?
Post by: Lycan on March 24, 2008, 05:23:12 PM
Hmm, does the issue presist if the AVG is uninstalled?
Please give that a shot.
Title: Re: Possible bug discovered?
Post by: fgl30 on March 25, 2008, 08:24:29 AM
unfortunatly, with or without AVG the problem persist.... I think this problem is with my ISP... 
Title: Re: Possible bug discovered?
Post by: Lycan on March 25, 2008, 08:55:09 AM
Well I don't think it's a bug in the firmware, however your unit may have gone south on you. Seems unlikely, but I'm failling to come up with another possible solution.
What is the make and model of the modem and who is the ISP?
Title: Re: Possible bug discovered?
Post by: Sammydad1 on March 25, 2008, 08:46:32 PM
Hi,

I had a problem kinda like this a while back.  I ended up replacing my cable modem.  Problem went away.

SD1
Title: Re: Possible bug discovered?
Post by: fgl30 on March 26, 2008, 05:21:02 AM
@Lycan: my modem is a Motorola SURFboard and my ISP is aŽsmall local CATV...

@Sammydad1: thx. IŽll try that.
Title: Re: Possible bug discovered?
Post by: Lycan on March 26, 2008, 10:28:50 AM
I'm leaning towards the modem as well. Auto negotation issue. See what other modems the ISP offers.
Title: Re: Possible bug discovered?
Post by: judas_iscariote on April 01, 2008, 09:19:36 PM
This smells like PMTU problem,

try this:

when the odd behavior happends, open cmd and type

Code: [Select]
ping www.google.com -f -l 1472

if ping does not fail, increase the 1472 number by one, till it fails. then you will see two different possible responses.

"packet needs to be fragmented but no DF is set"

or
"request time out "

if you see that latter message "Request timeout"  then your ISP is broken. to workaround it do this:

go to the router admin page, "Setup" then  "manual internet connection setup"

find the MTU box , there is a number there, substract 32 to it, save and reboot, try again.
Title: Re: Possible bug discovered?
Post by: Lycan on April 02, 2008, 11:55:22 AM
Good info.  ;D
Title: Re: Possible bug discovered?
Post by: judas_iscariote on April 02, 2008, 12:24:24 PM
if you see that latter message "Request timeout"  then your ISP is broken

If this is really your case, I urge you or any other person that has this problem to change ISP ASAP, this is a frecuent but CRITICAL firewall misconfiguration, caused by sysadmins reading ill-advised security literature..

more info on this subject http://www.znep.com/~marcs/mtu
Title: Re: Possible bug discovered?
Post by: fgl30 on April 03, 2008, 06:11:10 PM
This smells like PMTU problem,

try this:

when the odd behavior happends, open cmd and type

Code: [Select]
ping www.google.com -f -l 1472

if ping does not fail, increase the 1472 number by one, till it fails. then you will see two different possible responses.

"packet needs to be fragmented but no DF is set"

or
"request time out "

if you see that latter message "Request timeout"  then your ISP is broken. to workaround it do this:

go to the router admin page, "Setup" then  "manual internet connection setup"

find the MTU box , there is a number there, substract 32 to it, save and reboot, try again.

ok, I have "packet needs to be....." with 1473.... what about that? Thx
Title: Re: Possible bug discovered?
Post by: judas_iscariote on April 03, 2008, 06:48:28 PM
ok, I have "packet needs to be....." with 1473.... what about that? Thx

Then it is not the problem I have described. sorry, no idea then.
Title: Re: Possible bug discovered?
Post by: AWDL on April 07, 2008, 10:06:18 AM
ok, I have "packet needs to be....." with 1473.... what about that? Thx

So ping XXX -l 1472 worked and 1473 failed.

Then lower the MTU on your DIr-655 to 1472 (Internet> Manual...setup>MTU)


Title: Re: Possible bug discovered?
Post by: midhenry on May 14, 2008, 02:29:54 PM
Your post was not completely clear....
Do you see the problem on both wired and wireless connections?

I'm betting that the problem is only occurring when you are connected wirelessly, and that it never occurs with a wired connection. (This is what I see with my set up)

A perfectly good reason to see a message saying that the web page will not load is because you have lost your connection to the router (i.e. the wireless connection has failed)

If the problem is loss of wireless connection, I suspect you are a) out of luck, or b) in for lots of frustrating configuration hacks to work around the problem of the DIR-655 being very susceptible to interference (i.e. it's a design problem that may or may not be mitigated in particular circumstances by changing channels, fiddling with WISH controls, unchecking WMM Enable and/or Short GI, etc.  -  all suggestions provided to me by D-Link support without fixing the problem for me so far.)
Title: Re: Possible bug discovered?
Post by: Lycan on May 14, 2008, 03:13:29 PM
I have a feeling that the MTU adjustment did the trick for him.