I wasn't quite accurate in my previous message....the MTU setting was actually 576, NOT 500. You apparently cannot set the MTU below 576, at least not on the Linksys rounter I am using.

.........Bob

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I wasn't quite accurate in my previous message....the MTU setting was actually 576, NOT 500. You apparently cannot set the MTU below 576, at least not on the Linksys rounter I am using.

.........Bob

Bob....you and I have pretty much the same setup. Linksys router and Roadrunner ISP. I had a conversation with Linksys and they had me set the MTU to manual and the MTU size to 1500 in the router. Been working fine ever since.

Maybe that will help you.

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Boinc....Boinc....Boinc....Boinc....

Actually, the diagnostic tool that lot of BOINC/Seti users need right now is a 15 lb or 20 lb diagnostic adjustment tool applied to the router(s) causing the problems.

My ISP has a peer connection to Cogent in Dallas/Fort Worth and I am not having any problems. So we can assume it is most likely not a Cogent Co. router.

I was hoping that by now several people having a solid can't connect or can't upload/download problem and their MTU still set at 1500 would have done the:

ping -f -l 1472 setiathome.ssl.berkeley.edu
ping -f -l 1472 66.28.250.125

(Windows XP PPPoE users might have to use 1452)

and if they got the Packet needs to be fragmented but DF set. to either ping command, would have done a tracert to the URL or IP address and posted it in this thread. That way, with several from different locations, it might be possible to "diagnose" which router(s) are causing the problem and where they might be located. Why diagnose each users problem and work around it when it is possible to diagnose the cause of the problem. I am sure there would be a BOINC/Seti user some where near there who would be more than happy to stop by Home Depot to pick up a suitable diagnostic adjustment tool and pay a visit to that routers location. ([i]I can just see the picture now on the National News, red faced Seti@home fanatic facing off with a blue faced ISP company PR representative at the door.[/i/])

I wasn't quite accurate in my previous message....the MTU setting was actually 576, NOT 500. You apparently cannot set the MTU below 576, at least not on the Linksys rounter I am using.

.........Bob

Bob,

The important part is that the best throughput will be somewhere between 1500 and 576.

-- Ned

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Actually, the diagnostic tool that lot of BOINC/Seti users need right now is a 15 lb or 20 lb diagnostic adjustment tool applied to the router(s) causing the problems.

While I agree that routers with poor firmware should be hit by a large hammer, about the only thing you learn by hitting a router with a hammer is how well the router itself fragments.

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I wasn't quite accurate in my previous message....the MTU setting was actually 576, NOT 500. You apparently cannot set the MTU below 576, at least not on the Linksys router I am using.

.........Bob

Bob....you and I have pretty much the same setup. Linksys router and Roadrunner ISP. I had a conversation with Linksys and they had me set the MTU to manual and the MTU size to 1500 in the router. Been working fine ever since.

Maybe that will help you.

Very interesting. More important, what version of firmware do each of you have in your Linksys router and what model and version is it?

I recall that there was a problem over three years ago with some of the Linksys routers and the MTU setting. (I was seeing the problem on my new Linksys BEFSR41 at random after powering it on.) If it was set to default, and not manually set to 1500 or some other valid value, then some of them would default to some almost random MTU value and cause problems. The problem was that the Unix OS Web Server running on the ARM-5 processor in the router was not initializing all of the RAM when booted, and the router code, seeing a nonzero value in the MTU location assumed that it had been set from the flash memory holding the user's settings. This was fixed in the last three firmware updates for those Linksys routers. The Linksys people know this and that is why they have you manually set the Linksys router's MTU to 1500 as a workaround.

I would have assumed they would have recommended updating your routers firmware to the current level that sets the default of 1500 correctly. (Not sure, but I seem to recall that the fix also set the MTU discovery bit in the router to ON by default.) Note the post by Trulayne where he said "I just upgraded my Linksys BEFSX41 router to the latest firmware" and his problems were fixed! I just assumed that anyone with an older Linksys Router would have already updated to one of the fixed firmware versions or the 8/3/2004 version of the firmware with the Security fixes.

This may be a workaround for users of Linksys routers (upgrading the firmware) but is not a solution to the problem (getting the network routers fixed) as it is causing others that are not using Linksys routers a problem.

Just to put in a note.

I am on DSL, running on a PPPoE connection, through a Linksys 4 port router, BEFSR41, that I have been running for about 3-4 years now, and never had any problems, never upgraded the firmware on it, haven't had to change any settings. Computer is on WinXP also. FWIW

Jeremy

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about the only thing you learn by hitting a router with a hammer is how well the router itself fragments.

Hee, hee, I wish I had thought of that one. But I just could not get past the thought of what the expression on the faces of the ISP's PR people would be if someone showed up carrying a 20 lb sledgehammer.

I am on DSL, running on a PPPoE connection, through a Linksys 4 port router, BEFSR41, that I have been running for about 3-4 years now, and never had any problems, never upgraded the firmware on it, haven't had to change any settings. Computer is on WinXP also. FWIW

Jeremy

It would all depend on the exact version of firmware and version of the hardware you have. The problem started when they upgraded their firmware with a new version of Unix to drive it. The problem did not show up in all hardware versions of the router either, as some versions of the hardware had memory that always reset to zero's when powered on. My brand new Router was not one of them.

And if the problem black hole routers are not in your path to Berkeley, you would not be seeing any problems anyway.

With all of these variables, no wonder it has taken so long to sort out any useful information on what this Linksys part of the problem is and what workarounds can be used in each case. Remember, there is a problem in the BOINC code that also causes the same type of symptom for some users. And I have been tracking down another low frequency failure problem that has the same symptoms, and that appears to be a random problem with the berkeley upload/download servers.

Very interesting. More important, what version of firmware do each of you have in your Linksys router and what model and version is it?

I am using a BEFSX41 Linksys router. The firmware is dated Oct. 20, 2003 (Version 1.45.6). There is a new firmware version, but I have not had any success at trying to upgrade. I keep getting a "file pattern error." In the mean time, I have reset the MTU to 1500 manual!. I'll have to tract down from Linksys what the "file pattern error" means, but while finding others with the same problem, I have yet to find the solution.

Ain't his fun? <chuckle>

.........Bob

Edited to add: Had to reduce the MTU to 1100 in order to connect.

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Bob, I had the same problem when I tried to update my firmware by using the update firmware from the "help" tab. I went to the Linksys website and talked to the helpdesk. They had me download a seperate installer. I used it and was successful with the update. ftp.linksys.com/pub/network/tftp.exe

NOTE: record any special setting before upgrading since everything will be set to default after the upgrade.

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FWIW, and not meaning to contribute to thread drift, I found the problem with upgrading my Linksys firmware. I was getting a "file pattern error."

As it turns out, the current firmware I was using has been upgraded twice. The unit balked when I tried to upgrade to the latest firmware. The solution was downloading and installing the previous upgrade.

You can find all the old upgrades at: FTP://FTP.linksys.com/pub/network

BOINC seems to be working just fine now! WHEW!!!

..........Bob

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Wander,

All of that is basically correct, and I'm not arguing against turning on the MTU blackhole detection.

My statement is that almost everything can handle a 1500 MTU, and the most common exceptions are PPPoE-type connections (typically 1480 for these).

If the machine that limits MTU is far away, then setting your MTU to match is a bad idea.

If the machine that limits MTU is very near (like your DSL connection) then everything is running at 1480 (or whatever the limit is) and setting your connection to that value will never hurt.

-- Ned

[edit]P.S. I suggested setting MTU to 500 or so as a diagnostic. 500 is very small, but if it does not work, MTU is not the problem, and you can pursue other problems.

If 500 does work, then you can try to find the largest possible value that works without error.[/edit]

Got it :-)

I really don't know whether or not the bad router is close by or not, and I don't know how to found this out (maybe tracert it and then pinging overy other machine in it?), but using that param fixed it for me, so...

Bob, good to hear that a upgraded firmware fixed it for you!

Cheers

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