Posts Tagged ‘centos’

Iptables rules loaded every time after a reboot

Thursday, November 7th, 2019

Even if it has been disabled firewalld and iptables, some iptables rules could be activated after a reboot. It’s due to libvirtd .

I’ve just read a good post here where it’s fully explained why even though iptables is turned OFF, after every boot the command iptables -L -n still displays some rules to be activated.

Execute Windows Commands from Linux using winexe

Tuesday, September 10th, 2019

I’ve just found a good tutorial to compile winexe.
My host was a CentOS 7 box and I followed the instruction of this link:

Execute Windows Commands from Linux using winexe. Connect from Linux to Windows without SSH

In order to have git working, I opened the outgoing connection of 9418 TCP port on my firewall.

Don’t ask me, I don’t know why…

Friday, February 7th, 2014

I’m telling You about a Centos 5.10 server joined to an Active Directory environment.
Once I was able to open a ssh session on this server with my A.D. username/password, but some day ago I noticed it was possible only to log in this server using local root account.
I discovered that the wbinfo -i myusername  command retuned a WBC_ERR_WINBIND_NOT_AVAILABLE error.

To fix this problem I issued the following commands:

  # service winbind stop
  # service smb stop
  # net cache flush
  # rm -f /var/lib/samba/*tdb
  # service smb start
  # service winbind start

How to remove the read failed after 0 of 4096 I/O error

Wednesday, September 18th, 2013

Recently in a very old server I had to remove a disk. My server was composed by two physical volumes: a RAID5 volume, shown as /dev/sda  to the operating system  by the SCSI controller, and a single hard disk as /dev/sdb.

My /dev/sdb, since there is no way to have a new disk with the same geometry, I decided to remove it.
The bios utility of my SCSI controller is quite strange and I cannot remove my une-disk logical volume without remove all the configuration.

root@arch:~# pvdisplay
  /dev/sdb: read failed after 0 of 4096 at 0: input/output Error
  /dev/sdb: read failed after 0 of 4096 at 146695716864: input/output Error
  /dev/sdb: read failed after 0 of 4096 at 146695774208: input/output Error
  /dev/sdb: read failed after 0 of 4096 at 4096: input/output Error
  — Physical volume —
  PV Name               /dev/sda1
  VG Name               vg_system
  PV Size               838,12 GiB / not usable 2,00 MiB
  Allocatable           yes
  PE Size               4,00 MiB
  Total PE              214559
  Free PE               21184
  Allocated PE          193375
  PV UUID               ZQQwAs-yGgP-LZXk-3cTy-yaOb-gijr-bnUCz4

So I’d better to leave my controller untouched and tell my linux CentOS to forget the /dev/sdb disk.

root@arch:~# echo 1 > /sys/block/sdb/device/delete

x2go

Friday, May 3rd, 2013

Thanks to a Sebastian’s post here, I noticed the existence of  x2go. I’ve just tested it and I liked it a lot. X2go is a very nice way to access my linux desktop.

In order to install x2go server-side, on a Centos 6.4 I only needed theese commands:

yum update
wget -O /etc/yum.repos.d/x2go.repo http://download.opensuse.org/repositories/X11:/RemoteDesktop:/x2go/RHEL_6/X11:RemoteDesktop:x2go.repo
yum update
yum install x2goserver

then

vi /etc/group

to add the guys to be allowed to connect to their desktop. E.g.

x2gouser:x:298:joe,jane,jack,jasmine

The x2go windows client can be downloaded from http://code.x2go.org/releases/binary-win32/x2goclient/releases/.

ORA-01034 and ORA-27121 on CentOS5

Thursday, April 30th, 2009

getting the error

ERROR: ORA-01034: ORACLE not available ORA-27121: unable to determine size of shared memory segment Linux Error: 13: Permission denied

on a CentOS 5 Oracle box, You can fix it with changing a file permission:

chmod 6751 $ORACLE_HOME/bin/oracle

Dreadful, is’t it? 😉