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34753 discussions

connection speeds between nodes
by wessel van der aart 09 Mar '11

09 Mar '11

Hi All, I've been asked to setup a 3d renderfarm at our office , at the start it will contain about 8 nodes but it should be build at growth. now the setup i had in mind is as following: All the data is already stored on a StorNext SAN filesystem (quantum ) this should be mounted on a centos server trough fiber optics , which in its turn shares the FS over NFS to all the rendernodes (also centos). Now we've estimated that the average file send to each node will be about 90MB , so that's what i like the average connection to be, i know that gigabit ethernet should be able to that (testing with iperf confirms that) but testing the speed to already existing nfs shares gives me a 55MB max. as i'm not familiar with network shares performance tweaking is was wondering if anybody here did and could give me some info on this? Also i thought on giving all the nodes 2x1Gb-eth ports and putting those in a BOND, will do this any good or do i have to take a look a the nfs server side first? thanks, Wessel

6 17

what is the “Online Certificate Status Protocol”
by erikmccaskey64 09 Mar '11

09 Mar '11

I use privoxy. In the user.action file i have a redirect rule and a few websites: { +redirect{s@http://@https://@} } .twitter.com .facebook.com Ok! it's working great, e.g.: if i visit any "*twitter.com" URL it gets redirected to HTTPS! But: with wireshark i can see some "OCSP" packets [ http://en.wikipedia.org/wiki/Online_Certificate_Status_Protocol ] Question: What are these packets? Why aren't there in HTTPS? Is my redirection method with privoxy is secure? Thank you for any tips/opinions!

2 1

Re: [CentOS] Internet connection sharing?
by hadi motamedi 09 Mar '11

09 Mar '11

On 3/8/11, Rudi Ahlers <Rudi(a)softdux.com> wrote: > On Tue, Mar 8, 2011 at 12:09 PM, hadi motamedi <motamedi24(a)gmail.com> wrote: >> On 3/8/11, Jakub Jedelsky <jakub.jedelsky(a)gmail.com> wrote: >>> Dne 8.3.2011 10:19, hadi motamedi napsal(a): >>>> Dear All >>>> My centos machine is connected to my MS Windows machine on the net.The >>>> MS Windows machine is connected to Internet via valid IP address >>>> setting and on its secondary ip address setting it can see my centos >>>> machine on the intranet.Can you please let me know how can try for >>>> Internet connection sharing such that my centos machine can see >>>> internet with minor modifications done? >>>> Thank you in advance >>> >>> Hi hadi, >>> >>> this isn't centos thing, all you need is to configure network bridge on >>> your Windows machine. You didn't send info about your windows verison so >>> try to google something about it >>> (http://www.google.com/#q=windows+network+bridge) >>> >>> JJ >>> _______________________________________________ >>> CentOS mailing list >>> CentOS(a)centos.org >>> http://lists.centos.org/mailman/listinfo/centos >>> >> Thank you very much for your reply.I am familiar with internet >> connection sharing on MS Windows as I have a third XP client on the >> same net connected to the internet.I tried as the following on my >> centos: >> #route add -net default gw 172.18.209.1 >> Where this is the secondary ip address of the MS Windows host.But the >> centos cannot see the internet. Can you please let me know why? >> _______________________________________________ > > > Did you add any DNS resovler IP's to /etc/resolv.conf ? > > > -- > Kind Regards > Rudi Ahlers > SoftDux > > Website: http://www.SoftDux.com > Technical Blog: http://Blog.SoftDux.com > Office: 087 805 9573 > Cell: 082 554 7532 > Yes, I did but still internet unreachable.

4 6

how to only allow tcp on dport 443 on the OUTPUT chain?
by erikmccaskey64 09 Mar '11

09 Mar '11

it's a normal desktop machines iptables firewall: If i want to block udp on dport 80 on the output chain, then is this enough? i want to only allow tcp on it! iptables -P OUTPUT DROP iptables -A OUTPUT -o $PUBIF --dport 80 -j ACCEPT or i need this rule? iptables -P OUTPUT DROP iptables -A OUTPUT -o $PUBIF -p tcp --dport 80 -j ACCEPT the second one is the good one?

1 0

Re: [CentOS] Creating the symbolic links in the /boot and /boot/grub/
by Nico Kadel-Garcia 09 Mar '11

09 Mar '11

On Wed, Mar 9, 2011 at 12:40 AM, Todd Cary <todd(a)aristesoftware.com> wrote: > My current kernel is "vmlinuz-2.6.9-89.35.1" per grub.conf: > > #boot=/dev/hdc > default=1 > timeout=5 > splashimage=(hd0,0)/grub/splash.xpm.gz > hiddenmenu > title CentOS (2.6.9-100.EL) > root (hd0,0) > kernel /vmlinuz-2.6.9-100.EL ro root=/dev/VolGroup00/LogVol00 rhgb quiet > initrd /initrd-2.6.9-100.EL.img > title CentOS (2.6.9-89.35.1.ELsmp) > root (hd0,0) > kernel /vmlinuz-2.6.9-89.35.1.ELsmp ro root=/dev/VolGroup00/LogVol00 rhgb > quiet > initrd /initrd-2.6.9-89.35.1.ELsmp.img > > What is the correct syntax for "rpm -U -replacepkgs [kernel-whatever].rpm" ? > What should go into [kernel-whaetver]? > > In like manner, I have forgotten how to do a query on it to see if it is > present as in > > # rpm -q [kernel-name] > > Sorry, but it has been a long time since I used rpm and my Admin book does > not give an example. > > Todd OK, this should all go to the list for other CentOS folks who run into this kind of adventure. To get the full list of RPM's, look at the syntax of the "/etc/cron.daily/rpm"nightly script. > man rpm to look up the available options and learn about them. It's usually worth learning about such an important command, and RPM components are what yum really uses, so it's helpful to understand. > rpm -qa | grep kernel to get the list of kernel related components. Because of this line in your grub.conf: kernel /vmlinuz-2.6.9-100.EL I can also deduce that the relevant vmlinuz file was at /boot/bmlinuz-2.6.9-100.EL, and you can use the command "rpm -q -f /boot/vmlinuz-2.6.9-100.EL" to figure out what package it belonged to. > rpm -q -f /boot/vmlinuz-2.6.9-100.EL --qf '%{name}-%{version}-%{release}.%{arch}.rpm\n' will get you the get the full package name of the actual kernel RPM. Download the latest RPM from your favorite CentOS repository, after all, updating your kernel is you got into this trouble in the first place. > rpm -U --replacepkgs [whatever the name of that actual downloaded rpm is] See, you shouldn't *care* about your actual running kernel. You wanted the update, right? Go for it!!!! The running kernel will present problems you want the most recent one.

1 0

Creating the symbolic links in the /boot and /boot/grub/
by Todd Cary 09 Mar '11

09 Mar '11

I started a new thread since the original one is getting rather long. I have retrieved the files I deleted in /boot and /boot/grub, however I need to make links for /boot/System.map (System.map -> System.map-2.6.9-89.35.1) /boot/vmlinuz (vmlinuz -> vmlinuz-2.6.9-89.35.1) /boot/grub/menu.lst (menu.lst -> ./grub.conf) If it was not so important to get it correct, I would appreciate the syntax for the command. Usually I would figure it out. Since I have restored the files (I will double check to make sure they are all there), do I need to run grub-install? My apologies for bothering everyone with such a dumb error on my part. Todd -- Ariste Software Petaluma, CA 94952 http://www.aristesoftware.com

2 1

centos home router-gateway network setup
by Mark Pryor 09 Mar '11

09 Mar '11

Hello, In the last 3 days I setup my SOHO in 2 ways (1) attempt using a retail wifi/router by Netgear. The wifi is not part of this question. WAN (TW Cable modem) | | Netgear (192.168.1.1) \ \ _____\______________ | eth0 | | \ | | \--br0--eth2 | | | | | C5.5 eth1 | | / | |_______ /___________| / / LAN (switch upstairs) above is my first setup for SOHO network. Only br0 had an IP (dynamic). All of the nics had proto None and were slaved to br0. This is a very easy setup. The whole network, from Netgear to LAN and beyond, is one subnet. (2) attempt - permanently remove the Netgear and have C5.5 do all the services- gateway, router, dhcp, and firewall. The only way I could get this to work was with no bridging at all. Each nic needed an IP and all on different subnets. eth0: dynamic from TW WAN eth1: static at 192.168.1.1 eth2: static at 192.168.3.1 Using the lokkit firewall tool and adding NAT/Masquerade to eth0 this worked. My question is: is there a way avoid a wasted IP at eth2 and somehow bridge it to or with eth1 so only one subnet is possible inside the LAN? I know I need at least one static IP on one of the nics for the gateway. -- Mark

2 1

Internet connection sharing?
by hadi motamedi 08 Mar '11

08 Mar '11

Dear All My centos machine is connected to my MS Windows machine on the net.The MS Windows machine is connected to Internet via valid IP address setting and on its secondary ip address setting it can see my centos machine on the intranet.Can you please let me know how can try for Internet connection sharing such that my centos machine can see internet with minor modifications done? Thank you in advance

10 23

Load balancing...
by Todd 08 Mar '11

08 Mar '11

Hi All, Can anyone help me hash out how best to load balance a website that is getting considerable traffic? In the past I only have experience with BigIP where you have a load balancing device that keeps track and send traffic to the best server possible at the time. This was a proprietary system that I think was something Dell rebranded. Right now, the whole site is is 400gb of video, HTML5, Apache, PHP, MySQL, runs on a single box with 16gb of RAM and mirrored /var/www/html (2x1tb raid level drives). I have a Comcast 50/10 connection, 5 statics and I am seeing about 125 unique visitors a day. The site runs fine, but in anticipation of more traffic as well as a learning experience I would like to load balance. Obviously I need a second server just like the one it is running on now. I will probably spec something out that is capable of 32gb of RAM. What about a dedicated load balancing device? What specs should this be? How much RAM, HD, processor? It is sufficient to buy something with a GB NIC and say 4gb of RAM? Can one go slower but more RAM, small HD? I don't really quite know how intensive a task this decision making process is for the load balancer.. Right now, as example, I have an Untangle Firewall and it runs on a old AMD with 2gb RAM, GB NIC and it seems to do just fine. My local computer store has several P4 2.8ghz with 2GB of RAM for like $99.... Can anyone enlighten me on specs, proper setup, caveats....? -Jason

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Re: [CentOS] Internet connection sharing?
by David Brian Chait 08 Mar '11

08 Mar '11

> Do you have any proof of this? OR are you making assumptions of past > experiences? We have many Windows server on the net, directly with > very few hassles. I have never had a *NIX server under my charge hacked, I have had several Windows machines (those directly connected to the internet) hacked. No, I am not a *NIX worshiper either, I happen to have 7 MS certs. With that said, each OS has stregnths and weaknesses, MS tends to function better as a user facing interface to windows desktop infrastructure, but I avoid it like the plague for public facing infrastructure.

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