Discuss June 2016

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114 participants
99 discussions

I want to connect to a l2tp server from centos.
by Eliezer Croitoru 22 Mar '17

22 Mar '17

I have a server currently connecting to a pptp remote server. This server(lns\lac) has the option for pptp connections and l2tp connections. The l2tp connections are not using ipsec encryption at all. I have seen couple guides\tutorials on the internet: - https://raymii.org/s/tutorials/IPSEC_L2TP_vpn_on_CentOS_-_Red_Hat_Enterpris… - https://wiki.archlinux.org/index.php/L2TP/IPsec_VPN_client_setup But all the guides that I have found are using ipsec with "secret". On ubuntu there is a gui applet that helps setting these kind of connections up but I am working with a CentOS server and not Ubuntu desktop. If someone used l2tp the same way I want to use on CentOS 7 please give me some advice. If you have a guide which might help me I will be more then happy to see this one. Thanks, Eliezer

4 8

CentOS-7-x86_64-GenericCloud.raw very unusual format
by Aliaksei Sheshka 15 Oct '16

15 Oct '16

Hello! Is anyone aware why CentOS-7-x86_64-GenericCloud.raw has such unusual format ? root@test-srv:~# wget http://cloud.centos.org/centos/7/images/CentOS-7-x86_64-GenericCloud.raw --2016-03-21 13:16:31-- http://cloud.centos.org/centos/7/images/CentOS-7-x86_64-GenericCloud.raw Resolving cloud.centos.org (cloud.centos.org)... 162.252.80.138 Connecting to cloud.centos.org (cloud.centos.org)|162.252.80.138|:80... connected. HTTP request sent, awaiting response... 200 OK Length: 374668382 (357M) [application/x-gzip] Saving to: 'CentOS-7-x86_64-GenericCloud.raw' CentOS-7-x86_64-GenericCloud.raw 100%[=========================================================================>] 357.31M 12.9MB/s in 30s 2016-03-21 13:17:03 (11.9 MB/s) - 'CentOS-7-x86_64-GenericCloud.raw' saved [374668382/374668382] Download reports [application/x-gzip] for raw file And indeed root@test-srv:~# file CentOS-7-x86_64-GenericCloud.raw CentOS-7-x86_64-GenericCloud.raw: gzip compressed data, last modified: Sat Feb 27 02:14:37 2016, from Unix Ok, lets uncompress: root@test-srv:~# zcat -d CentOS-7-x86_64-GenericCloud.raw > CentOS-7-x86_64-GenericCloud.a And check again root@test-srv:~# file CentOS-7-x86_64-GenericCloud.a CentOS-7-x86_64-GenericCloud.a: POSIX tar archive (GNU) Ok. it's a tar archive. root@test-srv:~# tar -xf CentOS-7-x86_64-GenericCloud.a -v CentOS-7-x86_64-GenericCloud-1602.raw Now it's CentOS-7-x86_64-GenericCloud-1602.raw file which is indeed raw What is the point to pack single raw file into the tar.gz and to name it raw ? Or it's just a mistake ? Thanks!

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[OT] disk utility showing message "the partition is misaligned by"
by g 26 Aug '16

26 Aug '16

greetings. centos 6.7 [current] 'disk utility' has started showing message; WARNING: The partition is misaligned by 2560 bytes. This may result in very poor performance. Repartitioning is suggested. for sdc5 - /home partition. /dev/sdc5 302243312 156348604 130534968 55% /home /dev/sdc7 80854912 57088 76683952 1% /hdd/c/07 other than time involved to backup sdc5, repartition is not a problem. to my thinking, but not recalling, with fsck; fsck -rN -t ext4 /dev/sdc5 * to check repairs fsck -r -t ext4 /dev/sdc5 * to repair gparted was used to partition drive. is pmagic live a better choice, or should i return fdisk because; =+=+= $ sudo fdisk -l /dev/sdc [sudo] password for geo: Disk /dev/sdc: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 4096 bytes / 4096 bytes Disk identifier: 0x0009ede7 Device Boot Start End Blocks Id System /dev/sdc1 * 1 103 819200 83 Linux Partition 1 does not end on cylinder boundary. /dev/sdc2 103 230 1024000 82 Linux swap / Solaris Partition 2 does not end on cylinder boundary. /dev/sdc3 230 2107 15073280 83 Linux /dev/sdc4 2107 121602 959844352 5 Extended /dev/sdc5 2108 42019 320587970+ 83 Linux Partition 5 does not start on physical sector boundary. =+=+= suggestions for correcting above boundaries also appreciated. help needed and greatly appreciated. -- peace out. If Bill Gates got a dime for every time Windows crashes... ...oh, wait. He does. THAT explains it! -+- in a world with out fences, who needs gates. CentOS GNU/Linux 6.7 tc,hago. g .

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Broadcom BCM4313 support broken with kernel 2.6.32-573.7.1.el6.centos.plus.x86_64?
by wwp 24 Aug '16

24 Aug '16

Hello, I noticed that with latest kernel (2.6.32-573.7.1.el6.centos.plus.x86_64), my laptop's Wifi doesn't work, whereas with previous kernel (2.6.32-504.30.3.el6.centos.plus.x86_64), it works fine. Is this a known issue or did I miss something new? BTW, `lspci` says: Broadcom Corporation BCM4313 802.11bgn Wireless Network Adapter (rev 01) Regards, -- wwp

2 2

vnc on C7
by Jerry Geis 14 Jul '16

14 Jul '16

I am trying to get a remote screen on C7. I did the following on C7 server: yum install tigervnc-server cp /lib/systemd/system/vncserver@.service /etc/systemd/system/vncserver@:1.service systemctl daemon-reload edit /etc/systemd/system/vncserver@:1.service and replace <USER> with myuser su - myuser run vncpassword to set password systemctl start vncserver@:1.service systemctl enable vncserver@:1.service Then when I use something like vncviewer from a windows laptop into the linux desktop I get the password prompt, but the next screen says "oh no, something went wrong". Did I do something wrong above? Thanks, Jerry

5 8

Re: [CentOS] CentOS-7 Screen black after boot
by Earl A Ramirez 12 Jul '16

12 Jul '16

On 30 Jun 2016 09:34, "Venkata Balaji N" <nag1010(a)gmail.com> wrote: > > Hello Community, > > This is my first ever email to CentOS community. Firstly, CentOS is a great > open-source operating system. I have been using it for years and > recommending the same for production use to our customers. > > I have installed CentOS-7 operating system couple of days ago and > everything was working fine. Yesterday, the screen got struck and the whole > system was unresponsive, after a long wait, i have restarted the system. > Since, then, i can only see the black screen and GUI is not coming up. > > I can remotely login to the system from Putty and can operate without any > issues, the only issue is that GUI is not coming up. > > I have installed CentOS-7 server-GUI. Any help would be appreciated here. > > Regards, > Venkata B N > _______________________________________________ > CentOS mailing list > CentOS(a)centos.org > https://lists.centos.org/mailman/listinfo/centos Are you seeing the same behaviour if you choose the diagnostic kernel which has very basic display support? What types or graphic card are you using?

4 7

.NET on Centos.
by Peter Q. 06 Jul '16

06 Jul '16

Hi there, I was reading about it. https://www.redhat.com/en/about/blog/net-core-now-available-and-supported-r… What will happen with Centos and .NET? In the side of security and stability.

6 7

OT: hardware, MegaRAID SAS 2008 (falcon)
by m.roth＠5-cent.us 05 Jul '16

05 Jul '16

I've been googling, and haven't yet found the answer: does anyone here know if a MegaRAID SAS 2008 (falcon) (rev 03) can handle drives bigger than 2TB? mark

3 5

netbook screen suddenly goes black
by Fred Smith 02 Jul '16

02 Jul '16

Hi all! I'm running an up to date Centos-7 on my Acer Aspire One netbook. have been for, well, ever since C7 was released. Just had an event today that also happened 2 or 3 times with earlier systems installed, but I never pursued it. What happens is that suddenly while working away on the desktop the display suddenly goes black... not black as in turned off, I can see that the backlight is still on, but no image is displayed. Nothing I can do fixes it except a reboot. I've tried CTRL-ALT-BKSP, CTRL-ALT-DEL, alt+printscreen+r+e+i+s+u+b. none of them do anything noticeable. I've been looking at system logs and don't find anything that gives me a clue what is going wrong when that happens. neither dmesg, /var/log/Xorg*, nor /var/log/messages contins much. I've tried digging thru "man journalctl" and ultimately reading thru the output of journalctl with no arguments. Can anyone of you provide further hints on what I should be looking for or at? thanks! Fred -- ---- Fred Smith -- fredex(a)fcshome.stoneham.ma.us ----------------------------- But God demonstrates his own love for us in this: While we were still sinners, Christ died for us. ------------------------------- Romans 5:8 (niv) ------------------------------

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[CENTOS ]IPTABLES - How Secure & Best Practice
by Leon Vergottini 01 Jul '16

01 Jul '16

Dear Members I hope you are all doing well. I am busy teaching myself iptables and was wondering if I may get some advise. The scenario is the following: 1. Default policy is to block all traffic 2. Allow web traffic and SSH 3. Allow other applications I have come up with the following: #!/bin/bash # RESET CURRENT RULE BASE iptables -F service iptables save # DEFAULT FIREWALL POLICY iptables -P INPUT DROP iptables -P FORWARD DROP iptables -P OUTPUT DROP # ------------------------------------------------------ # INPUT CHAIN RULES # ------------------------------------------------------ # MOST COMMON ATTACKS iptables -A INPUT -p tcp --tcp-flags ALL NONE -j DROP iptables -A INPUT -p tcp ! --syn -m state --state NEW -j DROP iptables -A INPUT -p tcp --tcp-flags ALL ALL -j DROP # LOOPBACK, ESTABLISHED & RELATED CONNECTIONS iptables -A INPUT -i lo -j ACCEPT iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT # SSH iptables -A INPUT -p tcp -m tcp --dport 22 -j ACCEPT # WEB SERVICES iptables -A INPUT -p tcp -m tcp --dport 80 -j ACCEPT iptables -A INPUT -p tcp -m tcp --dport 443 -j ACCEPT iptables -A INPUT -p tcp -m tcp --dport 8080 -j ACCEPT # EMAIL iptables -A INPUT -p tcp -m tcp --dport 143 -j ACCEPT iptables -A INPUT -p tcp -m tcp --dport 993 -j ACCEPT # OTHER APPLICATIONS iptables -A INPUT -p tcp -m tcp --dport XXXXX -j ACCEPT iptables -A INPUT -p tcp -m tcp --dport XXXXX -j ACCEPT # ------------------------------------------------------ # OUTPUT CHAIN RULES # ------------------------------------------------------ # UDP iptables -A OUTPUT -p udp -j DROP # LOOPBACK, ESTABLISHED & RELATED CONNECTIONS iptables -A OUTPUT -i lo -j ACCEPT iptables -A OUTPUT -m state --state ESTABLISHED,RELATED -j ACCEPT # SSH iptables -A INPUT -p tcp -m tcp --dport 22 -j ACCEPT # WEB SERVICES iptables -A INPUT -p tcp -m tcp --dport 80 -j ACCEPT iptables -A INPUT -p tcp -m tcp --dport 443 -j ACCEPT iptables -A INPUT -p tcp -m tcp --dport 8080 -j ACCEPT # EMAIL iptables -A INPUT -p tcp -m tcp --dport 143 -j ACCEPT iptables -A INPUT -p tcp -m tcp --dport 993 -j ACCEPT # OTHER APPLICATIONS iptables -A INPUT -p tcp -m tcp --dport 11009 -j ACCEPT iptables -A INPUT -p tcp -m tcp --dport 12009 -j ACCEPT # ------------------------------------------------------ # SAVE & APPLY # ------------------------------------------------------ service iptables save service iptables restart To note: 1. The drop commands at the beginning of each chain is for increase performance. It is my understanding that file gets read from top to bottom and applied accordingly. Therefore, applying them in the beginning will increase the performance by not reading through all the rules only to apply the default policy. 2. I know the above point will not really affect the performance, so it is more of getting into a habit of structuring the rules according to best practice, or at least establishing a pattern for myself. How secure is this setup? Is there any mistakes or things that I need to look out for? Thank you in advance for your feedback. Kind Regards Leon

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Discuss June 2016