# SSH: Corrupted MAC on input

## ziererk

Hi,

last week, I updated the kernel from hardened-sources-2.6.11-r15 to hardened-sources-2.6.14-r1. Since that, the nightly backup job crashes every around second night with the error "Corrupted MAC on input" (witch means: data corruption).

I had to modify the kernel sources with SysKonnect-Networkdrivers, because my Yukon2-Chipset isn't supported, yet. But I used the same drivers (a little older version) with the last kernel without problems.

I this problem more related to the network driver, to grsecurity or to the new kernel 2.6.14? Where should I ask at best, or can anyone from the gentoo forum help me with this? Has anyone else a similar problem with the new hardened-sources?

Thank you.

Klaus

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## dberkholz

The easy test here is duplicating with vanilla-sources. That tells you whether it's hardened vs vanilla.

You can try vanilla 2.6.14 to check whether it's hardened vs vanilla (or just disable grsec etc). If it works there, it's hardened problems. If it doesn't, it could be the kernel version or your network driver.

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## ziererk

My problem is, this is a production server. I cannot switch kernels just to experiment. And the second problem is... This error happens only sporadically.

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## dberkholz

The usual time this error message comes up is with flaky hardware -- try replacing your Ethernet card with somethin better. Also make sure it happens when connecting to more than one different computer.

I just ran into it a week or two ago.

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## ziererk

Well, this is a onboard chip, and the server is 1HE (hight unit, don't know, how this is written in english). I don't think, it's on the network chip, but the driver in combination with the new kernel. I'll next try hardened-sources-2.6.14-r3 and report that error to SysKonnect, if that doesn't help.

Thank you.

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## dberkholz

1U is how we refer to it.

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