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Chastan
join:2002-02-10
Pleasant Hill, CA

Chastan to xabba

Member

to xabba

Re: Linksys BEFSR81 Router: MTU Settings

I had the 2.40.2 firmware installed, and the router would occasionaly "crash" (Diag light staying on constantly). Although I lost some functionality, I downgraded to 2.38.whatever and it's been stable.
RobertKop
join:2000-09-22
Milwaukee, WI

RobertKop

Member

I am having the same trouble with my BEFSR81, v. 2.40.2. It starts up fine, but every now and then the DIAG LED comes on and I need to reset the router, then things work fine. I wonder if this is the firmware or something to do with Windows XP. It seems that I may need to revert to an earily version of the firmware as well.
[text was edited by author 2002-03-18 13:29:53]

FROSTY
MVM
join:2000-08-10
Leeds, AL

FROSTY to Chastan

MVM

to Chastan
Odd.
Your router probably didn't take the 2.40.2 firmware correctly.

If you want to use 2.40.2, try the following:

Download 2.40.2 again.
Reset the router to factory defaults
Cycle power on the router.
Flash router to 2.40.2
Cycle power again on the router.
Reset to factory defaults again
Cycle power one more time.
Proceed to log into router and set it up.
Reboot router before use.

I have yet to experience such a lockup problem and I have used the router with Win 9x, 2K, XP, and Linux with no problems.

Are you using cable or DSL?
Are you changing the MTU option to an odd MTU value?

If your router continues to hang with 2.40.2, then either the router is bad, or a configuration error in causing the crash.

[text was edited by author 2002-03-18 13:49:59]
RobertKop
join:2000-09-22
Milwaukee, WI

RobertKop

Member

Frosty,

Thanks for the suggestion. I have reset and flashed my router as you outlined. It's too early to tell if it has worked. Also, I have DSL (ADSL) through, Telocity/Directv with Ameritech as the last mile service provider. And I have not tried to alter the MTU on the router, the setting is currently disabled. (I don't know if this means anything.)
Krozar7
join:2000-06-29
Meridian, ID

Krozar7 to RobertKop

Member

to RobertKop
I also experienced this same problem. Mine would crash every 1 - 2 days. I reflashed the firmware several times, but the problem still kept occuring. I finally flashed backward and the problem has not presented itself again in 6+ weeks. I think there may be something in 2.40.2 that causes the crash. I am waiting for the next firmware release to come out. If anyone knows of a beta firmware out there, let me know.

RWL
join:1999-07-24
Bellflower, CA

RWL

Member

Had the same problem, linksys exchanged the unit (it was less than year old. Now runs 24/7 without resets.
v2.40.2 firmware, pppoe enabled, mtu set at 1492

New unit has small power transformer.
[text was edited by author 2002-04-03 23:58:38]
mfortunato
join:2002-03-16
Thousand Oaks, CA

mfortunato to Krozar7

Member

to Krozar7
I had a different problem. The unit was dead immediately upon a failed attempt to download the new firmware. It would not accept a download of any firmware after that no matter what.
mfortunato

mfortunato to RWL

Member

to RWL
That was my solution as well. I wonder if they would still do this after one year? after all it is a latent defect that the device can die upon an attempted firmware download.
mfortunato

mfortunato

Member

Can someone explain this. As stated before, I have set my BEFSR81 to MTU=1492. I also set the MTU for my NIC to 1492 but, using ping -f -l found that I could not go above 1400 without fragmenting.

Today I checked out my wife's OLD computer and found that teak tests said it was running at 1492. I thought that was funny since I had never changed any of the registry settings. Tweak tests also said that RWIN = 10164 which is exactly 7 x the MSS. I ran DRTCP and it reported the MTU and RWIN as being blank!?!? so somehow that machine KNEW to use 1492 (i.e. optimal) and 7 x the MSS for RWIN?!?!?

So I ran back to my relatively new and way more powerful machine. I ran DRTCP and deleted the RWIN and MTU fields. I rebooted and pinged and found that I still could go no higher than MTU=1400. I ran tweak tests and, guess what, it reported MTU of 1400 and RWIN of 9520 - exactly 7x the MSS. I ran DRTCP again and MTU and RWIN are blank.

So what is going on here?

Why do both machines "KNOW" to set the MTU and RWIN where they do? (note her machine runs win98 and mine runs 98se)

Why does my machine seem to limit MTU to 1400?

I would appreciate any inputs.

Ed Wilts
@merrillcorp.com

Ed Wilts to Krozar7

Anon

to Krozar7
I too have had repeated lockups with 2.40.2. Diag light comes on and the unit is not even pingable from the inside. A quick reset (power off/on) will get it going for another day or two. I've been working this with Linksys for a few weeks, and they finally decided that my unit was bugsted and to send me a replacement. It arrived today so I'll install this weekend and see what happens.

.../Ed
mailto:ewilts@ewilts.org
chadwick8
join:2002-04-17

chadwick8 to RWL

Member

to RWL
I've had similar problems with BEFSR81 units resetting.

I'm on my second unit now. Both exhibited identical behavior in my environment. Every "so often" (not on periodic intervals) the router resets. The front panel goes through the full power on self test routine, and it continues on happily afterwards.

The only reason the user notices usually is that the DNS server it returns on the initial DHCP request is 18.234.0.0, so nothing works until you request a DHCP address again.

I would have assumed just bad hardware, and I did with the first unit. It's remarkable that the second unit is exihibiting the same behavior. Hmmm...

Re-flashing of the unit to 2.42.2 has made no difference. I haven't tried downgrading the firmware yet.

I make heavy use of Windows XP on my LAN. I'm wondering of the XP machines are broadcasting UPnP requests and causing the router to crash?

Kind of a bummer. I've been using the BEFSR41 for months happily, but I wanted the SNMP support so I could run mrtg.

FROSTY
MVM
join:2000-08-10
Leeds, AL

FROSTY

MVM

Something I've noticed with these SR81 routers.

I've heard this 'reboot at random' is a sign of a faulty router.

I believe the source of the problem is a faulty power supply.
Here's proof to back up this theory.

I had the same problem with an older 8 port Linksys switch (the big clunky white one). It kept rebooting at random and I was beginning to think the switch was burning out. Turned out to be the power supply!!! Believe it or not, the SR81 power supply is the same model as the power supply for this 4 year old switch!!! Both power supplies have the same input and output power ratings.

I took the old power supply for the old switch and hooked it up to my SR81. The SR81 started rebooting constantly to the point where the orange DIAG light stayed solid. At the same time, I hooked the SR81's power supply to the old switch and it worked flawlessly. I switch the power supplies back, and the SR81 works flawless while the switch reboots constantly.

Even a Fluke 87 multimeter revealed the older power supply's DC voltage was not consistent. Thus causing the problems.

ewilts
@attbi.com

ewilts to Ed Wilts

Anon

to Ed Wilts
I'm happy to report that the replacement Linksys has been flawless. It's the newer version of the same unit and came with 2.40.2. I can definitively state that the firmware is *not* the problem - if you get repeated diag lights with lockups, replace the unit. I certainly am glad I did.

Linksys also did a "cross-ship" - they shipped me a new unit and after it arrived, I shipped my defective unit back. The new unit came complete in a shrink-wrapped box, just like you'd buy it from a store. No refurb unit here! I'm happy with the Linksys and the service they provided.

.../Ed
mailto:ewilts@ewilts.org