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Re: [CentOS] Linux TCP flaw
by Andrew Dent 12 Aug '16

12 Aug '16

Thanks for the info Peter. The VPS is running on a Plesk environment. ------ Original Message ------ From: "Peter" <peter(a)pajamian.dhs.org> To: centos(a)centos.org Sent: 12/08/2016 3:36:32 PM Subject: Re: [CentOS] Linux TCP flaw >On 12/08/16 17:33, Andrew Dent wrote: >> So after reading this, felt I should apply the fix to a CentOS6 VPS >>that >> I have. >> >>http://www.zdnet.com/article/linux-tcp-flaw-lets-anyone-hijack-internet-tra… >> >> [root@vps ~]# uname -r >> 2.6.32-042stab108.7 > >That's not a CentOS kernel, it's an openvz kernel that is not provided >by CentOS. The fixes and workarounds shown on the internet will not >work with that kernel. > >I suggest you find a better VPS provider, what you have is essentially >a >glorified chroot, not a real VPS and there are many aspects of CentOS >that are simply broken in that model. > > >Peter >_______________________________________________ >CentOS mailing list >CentOS(a)centos.org >https://lists.centos.org/mailman/listinfo/centos

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script to make webpage snapshot
by Valeri Galtsev 12 Aug '16

12 Aug '16

Dear Experts, Could someone recommend a script or utility one can run from command line on Linux or UNIX machine to make a snapshot of webpage? We have a signage (xibo) and whoever creates/changes content, likes to add URLs of some webpages there. All works well if these are webpages on our servers (which are pretty fast), but some external servers often take time to respond and take time to assemble the page, in addition these servers sometimes get really busy, and when response is longer than time devoted for that content in signage window, this window hangs forever with blank white field until you restart client. Trivial workaround: just to get snapshot (as, say daily cron job), and point signage client to that snapshot definitely will solve it, and simultaneously we will stop bugging other people servers often without much need for it. But when I tried to search for some utility or script that makes webpage snapshot, I discovered that my ability to search degraded somehow... Thanks for all your pointers! Valeri ++++++++++++++++++++++++++++++++++++++++ Valeri Galtsev Sr System Administrator Department of Astronomy and Astrophysics Kavli Institute for Cosmological Physics University of Chicago Phone: 773-702-4247 ++++++++++++++++++++++++++++++++++++++++

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Linux TCP flaw
by Andrew Dent 12 Aug '16

12 Aug '16

Hi So after reading this, felt I should apply the fix to a CentOS6 VPS that I have. http://www.zdnet.com/article/linux-tcp-flaw-lets-anyone-hijack-internet-tra… The article doesn't talk about CentOS or Redhat, but I assume the problem is the same, and hoping the solution is the same. However that doesn't seem to be the case. [root@vps ~]# uname -r 2.6.32-042stab108.7 [root@vps ~]# sysctl -a | grep ack_limit net.ipv4.tcp_challenge_ack_limit = 100 [root@vps ~]# vi /etc/sysctl.conf > Append > net.ipv4.tcp_challenge_ack_limit = 999999999 > to end of file [root@vps ~]# sysctl -p net.ipv4.ip_forward = 0 net.ipv4.tcp_syncookies = 1 error: permission denied on key 'net.bridge.bridge-nf-call-ip6tables' error: permission denied on key 'net.bridge.bridge-nf-call-iptables' error: permission denied on key 'net.bridge.bridge-nf-call-arptables' error: permission denied on key 'net.ipv4.tcp_challenge_ack_limit' [root@vps ~]# sysctl -a | grep ack_limit net.ipv4.tcp_challenge_ack_limit = 100 Am I getting a permission denied because of there is a different solution, or the problem doesn't apply to our VPS or some other reason? Regards Andrew Dent

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how to install opencl on centos 6.7
by qw 12 Aug '16

12 Aug '16

Hi, I'm building x264, and want to use opencl acceleration function. How to install opencl on centos 6.7 to support intel integrated GPUs for 'Intel(R) Xeon(R) CPU E5-2640 v3'? Thanks! Regards andrew

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how to install opencl on centos 6.7
by qw 12 Aug '16

12 Aug '16

Hi, I'm building x264, and want to use opencl acceleration function. How to install opencl on centos 6.7 to support intel integrated cpu for 'Intel(R) Xeon(R) CPU E5-2640 v3'? Thanks! Regards andrew

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Re: [CentOS] script to make webpage snapshot
by Valeri Galtsev 12 Aug '16

12 Aug '16

On Thu, August 11, 2016 5:13 pm, Dave Stevens wrote: > Quoting Valeri Galtsev <galtsev(a)kicp.uchicago.edu>: > >> >> On Thu, August 11, 2016 5:02 pm, John R Pierce wrote: >>> On 8/11/2016 1:46 PM, Valeri Galtsev wrote: >>>> Could someone recommend a script or utility one can run from command line >>>> on Linux or UNIX machine to make a snapshot of webpage? >>>> >>>> We have a signage (xibo) and whoever creates/changes content, likes to add >>>> URLs of some webpages there. All works well if these are webpages on our >>>> servers (which are pretty fast), but some external servers often take time >>>> to respond and take time to assemble the page, in addition these servers >>>> sometimes get really busy, and when response is longer than time devoted >>>> for that content in signage window, this window hangs forever with blank >>>> white field until you restart client. Trivial workaround: just to get snapshot (as, say daily cron job), and point signage client to that snapshot definitely will solve it, and simultaneously we will stop bugging >>>> other people servers often without much need for it. >>>> >>>> But when I tried to search for some utility or script that makes webpage >>>> snapshot, I discovered that my ability to search degraded somehow... >>> >>> many/most webpages these days are heavily dynamic content, a static snapshot would likely break. plus any site-relative links on that snapshot would be pointing to your server, not the original, any ajax code on that webpage would try to interact with your server which won't be running the right back end stuff, etcetc. >> >> I usually am not good at explaining what I need. I really only need an image of what one would see in web browser if one point to that URL. I do >> not care it to be interactive. I also don't want to get the content ("mirror") of stuff that URL points to on variety of "depths" - I don't want to use wget or curl for this reason. That is what I tried first and it breaks with at lest one of the web sites - they do seem protect themselves from "robots" or similar. And we don't need it. We just need to >> show what they page shows today, that's all. >> >> Valeri > > why not File -> Print -> .pdf? This involves a person sitting with open web browser and clicking mouse. I need to do it for a few webpages once a day, as they change daily. I prefer to once spend time on making cron job, and forget about it forever. Hence I need it done from command line. Valeri > > D > >> >>> >>> -- >>> john r pierce, recycling bits in santa cruz >>> >> >> >> ++++++++++++++++++++++++++++++++++++++++ >> Valeri Galtsev >> Sr System Administrator >> Department of Astronomy and Astrophysics >> Kavli Institute for Cosmological Physics >> University of Chicago >> Phone: 773-702-4247 >> ++++++++++++++++++++++++++++++++++++++++ >> _______________________________________________ >> CentOS mailing list >> CentOS(a)centos.org >> https://lists.centos.org/mailman/listinfo/centos >> > > > > -- > "As long as politics is the shadow cast on society by big business, the attenuation of the shadow will not change the substance." > > -- John Dewey > > > > > ++++++++++++++++++++++++++++++++++++++++ Valeri Galtsev Sr System Administrator Department of Astronomy and Astrophysics Kavli Institute for Cosmological Physics University of Chicago Phone: 773-702-4247 ++++++++++++++++++++++++++++++++++++++++

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Is "xman" available in any CentOS 6.x repo?
by Kay Schenk 12 Aug '16

12 Aug '16

I know it's old but I miss "xman" in CentOS 6. :( -- -------------------------------------------- MzK "Time spent with cats is never wasted." -- Sigmund Freud

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CentOS 7: System log has repeated lines: Started session 123 of user root.
by therbur 11 Aug '16

11 Aug '16

The system log (/var/log/messages) of a CentOS 7.2 system has frequently-repeated message line pairs like: Jul 18 14:00:01 localhost systemd: Started Session 307 of user root. Jul 18 14:00:01 localhost systemd: Starting Session 307 of user root. where the session number increases each time. Looking around on this, e.g. Red Hat Bugzilla bug 727315, it looks like it's when crond starts a task; it looks like it might be fixed - I would think that would be in CentOS but don't know how to find/compare the Fedora and CentOS systemd versions to know for sure. I found a post on a workaround - in /etc/systemd/system.conf to change the line: #LogLevel=info to: LogLevel=notice I did that and rebooted, and it has stopped the messages. I'm worried though that this may have knocked out something of actual interest from the syslog. So my question is, is there a better way? A way that info messages could go to some other log, or better yet, a way that those particular "session" messages, and only those, could go to some other log or be filtered out?

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Missing announcement for qemu-kvm
by Leonard den Ottolander 11 Aug '16

11 Aug '16

Hello, Received an update for qemu-kvm and qemu-img today, but the corresponding announcement is missing. Haven't received any messages since August 3rd, so there might be other announcements that haven't made it to the list yet. Regards, Leonard. -- mount -t life -o ro /dev/dna /genetic/research

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OT: trying to configure Ubuntu 14 to use dhcp
by m.roth＠5-cent.us 11 Aug '16

11 Aug '16

This is very much *not* CentOS, but if anyone knows how to do it *correctly*, please drop me an email offlist. mark

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