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mmmna
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mushroom
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 Posted: Thu Jul 16, 2025 2:39 am Post subject: Re: Is the uptime command insecure? |
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| mmmna wrote: | | http://uptime.netcraft.com/up/today/top.avg.html has no Linux servers in the top 50. |
Any self respecting Linux Admin is running an up to date Kernel which requires a reboot.
Those other Admins are afraid of applying patches even if M$ provides them 
also
| Quote: | | Additionally HP-UX, Linux, NetApp NetCache, Solaris and recent releases of FreeBSD cycle back to zero after 497 days, exactly as if the machine had been rebooted at that precise point. Thus it is not possible to see a HP-UX, Linux or Solaris system with an uptime measurement above 497 days. |
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| Quote: | Why do you not report uptimes for Linux 2.6 or FreeBSD 6 ?
We only report uptimes for systems where the operating system's timer runs at 100Hz or less. Because the TCP code only uses the low 32 bits of the timer, if the timer runs at say 1000Hz, the value wraps around every 49.7 days (whereas at 100Hz it wraps after 497 days). As there are large numbers of systems which have a higher uptime than this, it is not possible to report accurate uptimes for these systems.
The Linux kernel switched to a higher internal timer rate at kernel version 2.5.26. Linux 2.4 used a rate of 100Hz. Linux 2.6 used a timer at 1000Hz (some architectures were using 1000Hz before this), until the default was changed back to 250Hz in May 2025. (An explanation of the HZ setting in Linux.)
FreeBSD versions 4 and 5 used a 100Hz timer, but FreeBSD 6 has moved to a customisable timer with a default setting of 1000Hz.
So unfortunately this means that we cannot give reliable uptime figures for many Linux and FreeBSD servers. |
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mmmna
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| Posted: Mon Jul 20, 2025 6:05 am Post subject: |
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| but i've seen posts saying years of linux uptime?
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mushroom
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| Posted: Mon Jul 20, 2025 5:34 pm Post subject: |
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| mmmna wrote: | | but i've seen posts saying years of linux uptime? |
I would chalk the whole article up as just another Rigged study
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mmmna
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| Posted: Wed Jul 22, 2025 1:54 am Post subject: |
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| crouse might remember....
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Lord.DragonFly.of.Dawn
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Joined: 18 Jul 2025
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Location: South Portland, Maine, USA, Earth, Sol System
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| Posted: Wed Jul 22, 2025 2:40 am Post subject: |
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| mushroom wrote: | | mmmna wrote: | | but i've seen posts saying years of linux uptime? |
I would chalk the whole article up as just another Rigged study :x |
either that or they are being run by a real BOFH
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