Data corruption (was: Re: Keepalive issues)

On Sat, 28 Apr 2001, Graham Leggett wrote:

> Nathan Lutchansky wrote:

Yeah, you're right. I guess I shouldn't be lazy about debugging this.

> Essentially before reverting to HTTP/1.0, first try switching Keepalives

Same problem happens regardless of whether keepalive is used, but that's not surprising, considering what the bug is.

I pulled out tcpflow just to see where things were hanging, and it's pretty clear that there's a bug here. When Netscape uses a PUT request to store the liprefs file, the data it sends gets corrupted on the way through the proxy. I've attached an example capture for both the data from the browser and the data from the proxy. Parts of the client data are being zeroed on the way through the proxy, and the data is being truncated. This explains why the symptom was Netscape hanging - the Content-length header has the correct length, but the proxy loses some data as well as corrupting it.

This definitely wasn't happening with the last build, so something changed in the last week that broke the proxy.

I would guess that this type of data corruption happens with post requests too, but I haven't tried it.

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I've tried this test with several hosts. Interestingly, the farther the host is from the server, the fewer problems it has. With a host on a local DSL line, the data still gets truncated, but there's no corruption. With a host on the other side of the continent, the data doesn't even get truncated. I have a feeling this is a synchronization issue, but I can't put my finger on it.

Any ideas? -Nathan

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| Nathan Lutchansky | lutchann@litech.org |  Lithium Technologies  |
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