I'm interested to find out what the fix action is on this. Is it working yet? If so, what'd you do to fix it? Do you have two DHCP servers on your LAN, as Richard suggests? That'll mess things up for sure and give strange symptoms such as you describe.

OK I do have three routers but only one is set to assign IPs. I have two crunchers on the same router, the only two MAC addresses that use it. It has been this way for eight months.

Before I asked I tried rebooting all routers and PCs. I even reinstalled BOINC and SETI on a freshly formatted HD. Everything worked except SETI downloads, uploads worked fine. The other PC on the same router never had a problem. The SETI server would always respond to every command, it was only the downloads that would freeze after a few bytes.

So connecting to and communicating with the server was not a problem, downloads stopping after a few bytes is. As of now I removed the router in the computer lab (an unheated porch)and it is working. After I recharge my brain I'm going to RTFM and set up a static IP to the cruncher. I looked for the usual routing problems before I asked.

Format C should have fixed any problem on my end; it is like being borne again washed of all past corruption.

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I thank all of you for the replays. The problem is with my LAN IP; why it only affects SETI and why in the middle of a download is a question for another time.

I sometimes get the same thing on one or another of my machines, but it seems to resolve itself after a while (several minutes to a few hours).

Perhaps you could try disabling and then re-enabling your network card on the machine in question?

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Perhaps you could try disabling and then re-enabling your network card on the machine in question?

I reset everything; format C. The router assigned the same IP the SETI server saw the last 223 times. I got a new IP from my router and the SETI server saw it and responded but the downloads still froze on the first one after a few bytes.

I'm 99 and 44/100% sure assigning a static IP, as Sirius B suggested, to the cruncher will keep this from happening again. Remember the downloads froze as I was suspending some tasks. The uploads kept working along wit every other program.

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Perhaps you could try disabling and then re-enabling your network card on the machine in question?

I reset everything; format C. The router assigned the same IP the SETI server saw the last 223 times. I got a new IP from my router and the SETI server saw it and responded but the downloads still froze on the first one after a few bytes.

I'm 99 and 44/100% sure assigning a static IP, as Sirius B suggested, to the cruncher will keep this from happening again. Remember the downloads froze as I was suspending some tasks. The uploads kept working along wit every other program.

Assigning a static IP - rather than finding and understanding the root cause of the problem - feels to me like the sledgehammer approach to computer maintenance. If it works for you on a private, wholly-owned, subnet that's fine: you can maintain the records of network topology (in your head, if nowhere else) and configure the next addition in a non-conflicting way.

But that doesn't work in a commercial setting. I used to work as a peripatetic consultant and trouble-shooter. I used to deal with this sort of thing for hard cash: my first question on arrival at a new site was usually 'how is your network configured - can you show me the IP addressing schema?' 99.44% of the time, the answer was a blank look and "What's that?" Kerr-ching - the first hour of paid time was taken up by working it out for myself from first principles.

And then advising the correction of glaring howlers, like allocating a static printer address in the middle of a non-excluded DHCP scope.

Three routers and only one of them has DHCP enabled in it? The one at the top of your hiearchy has DHCP enabled and you're using the other two as dumb hubs? Not sure how that would work. If your top DHCP server assignes the WAN side of one of your disabled DHCP dumb hubs an IP address and that disable DHCP dumb hub assigns the same IP address to one of your crunchers (can't be disabled and still work, can it?), that may be a problem. Haven't really tried something like that to see how it works. But I'm thinking now it's probaby where your problem might be. The WAN side of your dumb hubs are going to request IP addresses and if you assign statics on the other side of your dumb hubs, that should work. I would make sure those statics are no where near the IPs your DHCP server hands out though.

Dumb hubs are cheap. If you're set up the way I think you may be set up, you could remove all doubt by having only one device capable of handing out IP addresses. I have one router feeding three of my crunchers, one directly off a router port, the other two are off a dumb hub which is off another port on the router. Another cruncher is connected wirelessly and I bridged the ethernet port to the wireless port. Off the ethernet port of that cruncher I have another dumb hub and I have a cruncher on that with plans to move/add more later.

Multiple DHCP servers? That's probably your problem. By chance the first iteration worked. By chance your current configuration is not working. Assigning statics off your disabled DHCP routers to your crunchers may fix it also.

I'm curious about what your physical topology looks like.

These days, you'd use dumb switches rather than dumb hubs, but apart from that you're right - both of them are transparent to IP addresses. You might get away with cascading routers if you only used the LAN side in dumb switch mode, but the moment you plug anything into the WAN port, you're managing two or even three subnets, and all the DHCP servers have to be configured just right. Remember, DHCP isn't managing just the IP addresses - gateway and DNS server addresses are also critical, though consumer-grade hardware does it's best to disguise this from you.

Assigning a static IP - rather than finding and understanding the root cause of the problem - feels to me like the sledgehammer approach to computer maintenance.

But that doesn't work in a commercial setting.

In a commercial setting I would be making 85K a year. I'm still tweaking the standard program and that is using all the brain cells I have for this type of work. I really dislike command line stuff but I will work with it as little as I can get away with. I just want to crunch wile the "polar vortex" makes the crunching good.

I have never had this problem with my network setup so I'm going to try a static IP only on the cruncher; all other machines will stay the way they have been for almost a year. I have to read the fine manual as it is to be able to do that; if I do something once a year I tend to forget how I did it last time.

I believe the SETI server seeing my machine on the newly formatted HD as the same machine from the old HD had something to do with it. I didn't try formatting C and installing with a different name though to prove this.

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