USA Linux Users Group Forum Index
Log in Register FAQ Memberlist Search USA Linux Users Group Forum Index Album

Is the uptime command insecure?

 
Post new topic   Reply to topic   printer-friendly view    USA Linux Users Group Forum Index » OTHER
View previous topic :: View next topic  
Author Message
mmmna
. . . .


Joined: 21 Apr 2024
Posts: 7224

PostPosted: Wed Jul 15, 2024 10:49 pm    Post subject: Is the uptime command insecure? Reply with quote

http://uptime.netcraft.com/up/today/top.avg.html has no Linux servers in the top 50.


Back to top
View user's profile Send private message
mushroom
Ultimate Member


Joined: 29 Jun 2024
Posts: 2129
Location: Queen Charlotte B. C. Canada

PostPosted: Thu Jul 16, 2024 2:39 am    Post subject: Re: Is the uptime command insecure? Reply with quote

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 Mad

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.

and
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 2024. (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.



_________________
SuSE 8.0, 8.2, 9.0, 9.1, 9.2, 9.3, 10.0, 10.1, 10.2, 10.3, 11.0, 11.1
Live CDs Mepis 8.0, Puppy 4.3.1, netbook- Zenwalk 6.2
Back to top
View user's profile Send private message Visit poster's website
mmmna
. . . .


Joined: 21 Apr 2024
Posts: 7224

PostPosted: Mon Jul 20, 2024 6:05 am    Post subject: Reply with quote

but i've seen posts saying years of linux uptime?



_________________
-Kubuntu 10.04 LTS Beta2 on Celeron D desktop
-PCLinuxOS 2024 LXDE on EeePC 900A with Atom n270 (modded with 32G SATA drive and 2G ram).
Back to top
View user's profile Send private message
mushroom
Ultimate Member


Joined: 29 Jun 2024
Posts: 2129
Location: Queen Charlotte B. C. Canada

PostPosted: Mon Jul 20, 2024 5:34 pm    Post subject: Reply with quote

mmmna wrote:
but i've seen posts saying years of linux uptime?

I would chalk the whole article up as just another Rigged study Mad



_________________
SuSE 8.0, 8.2, 9.0, 9.1, 9.2, 9.3, 10.0, 10.1, 10.2, 10.3, 11.0, 11.1
Live CDs Mepis 8.0, Puppy 4.3.1, netbook- Zenwalk 6.2
Back to top
View user's profile Send private message Visit poster's website
mmmna
. . . .


Joined: 21 Apr 2024
Posts: 7224

PostPosted: Wed Jul 22, 2024 1:54 am    Post subject: Reply with quote

crouse might remember....



_________________
-Kubuntu 10.04 LTS Beta2 on Celeron D desktop
-PCLinuxOS 2024 LXDE on EeePC 900A with Atom n270 (modded with 32G SATA drive and 2G ram).
Back to top
View user's profile Send private message
Lord.DragonFly.of.Dawn
Advanced Member


Joined: 18 Jul 2024
Posts: 607
Location: South Portland, Maine, USA, Earth, Sol System

PostPosted: Wed Jul 22, 2024 2:40 am    Post subject: Reply with quote

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



_________________
ArchLinux x86_64 - Custom Built Desktop
ArchLinux x86_64 - Compaq CQ50 Laptop
ArchLinux i686 - Acer Aspire One Netbook
ArchLinux i686 - Dell Presario ze2000 (w/ shattered LCD)

PuppyLinux, CloneZilla, PartedMagic, DBAN - rescue thumbdrives
Windows 7 (x86_64 desktop alternate boot)
Back to top
View user's profile Send private message Visit poster's website
Display posts from previous:   
Post new topic   Reply to topic   printer-friendly view    USA Linux Users Group Forum Index » OTHER All times are GMT
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
All content © 2024-2009 - Usa Linux Users Group
This forum is powered by phpBB. © 2024-2009 phpBB Group
Theme created by phpBBStyles.com and modified by Crouse