A relocatable RPM package can change its installation path during the setup process. Not all RPM packages can be installed into a custom directory. Use the following command to see if a specific package can be relocated. # rpm -qpi <rpm package> | grep Relocations To check rpm packages, centos-lsb-1.3-3.1.EL3.i386.rpm and rsync-2.5.7-5.3E.i386.rpm: # rpm -qpi …

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Install setroubleshoot-server as follows. # yum install -y setroubleshoot-server If the system is in enforcing or permissive mode, setroubleshoot will provide a user-friendly explanation about the AVC's. When there's AVC denial, messages like those below will print to /var/log/messages. Jul 14 09:52:03 desktop setroubleshoot: SELinux is preventing 57656220436F6E74656E74 from write access on the file firefox52.pdf. …

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Install the semanage command as follows. CentOS 5 rpm: policycoreutils CentOS 6 & 7 rpm: policycoreutils-python CentOS / AlmaLinux 8 rpm: policycoreutils-python-utils Execute the following command, replacing PORT with the desired TCP port number (11111). # semanage port -a -t ssh_port_t -p tcp PORT If a standard port is chosen, such as 443, the command …

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Disabling SELinux is not advised. Only turn off SELinux if your regulatory framework permits you to omit some measures of security reporting and enforcement. If SELinux is later turned on, files made while disabled will not have the proper labels. If you decide to turn SELinux back on, you'll need to rename all of your …

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To resolve this error, upgrade the BIOS/Firmware software to the latest version available. These are just informational messages which are logged on the server. Whenever a new CPU is added, the firmware script checks for that CPU's firmware and requests for firmware. Hence the message is logged in the messages file. # cat var/log/messages*|grep firmware …

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For the GFS2 filesystem to be mounted on multiple nodes, you must ensure that the total number of Filesystem journals is equal to the number of nodes. The number of available journals may be insufficient to successfully mount the GFS2 fs on all nodes of the cluster after a new node has been added. To …

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Why errors are received when changing IPv6 kernel parameters? # sysctl -p error: "net.ipv6.conf.default.accept_redirects" is an unknown key error: "net.ipv6.conf.default.accept_ra" is an unknown key error: "net.ipv6.conf.all.disable_ipv6" is an unknown key error: "net.ipv6.conf.default.disable_ipv6" is an unknown key Internet Protocol Version 6 (IPv6) is enabled by default in AlmaLinux and CentOS. However, some users might find it …

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Run the command vgimportdevices -a if every drive on the AlmaLinux server is a PV that this system can use. Only the multipath map will be added by vgimportdevices -a if a LUN is multipathed. Run lvmdevices --adddev [device name] for each device that will be used if just part of the disks contain the …

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The cups-lpd package must be installed and set up in order to accept requests to print using the LPD protocol on port 515. (in addition to a properly configured CUPS system). In all versions of CentOS, first install the cups-lpd package as follows. yum install cups-lpd Depending on the CentOS version you are using, there …

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When many users are printing at once, CUPS is very slow. The following error is seen repeatedly in the file /var/log/cups/error_log. E [09/Jul/2013:10:06:00 +0200] [Job 865106] Unable to reserve port: Resource temporarily unavailable The firewall blocks connections initiated from low-numbered TCP ports (port numbers less than 1024). This blocks CUPS outgoing LPD (Line Printer Deamon) …

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The root cause of this error is that the policy file is corrupted or empty. After turning on SELinux, the system is unable to boot. The screen displays the following messages and the booting process does not continue. [ OK ] Reached target Switch Root. Starting Switch Root... [!!!!!!] Failed to load SELinux policy, freezing …

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To set up a print queue that will send the print job to a file, carry out the following operations as root. Add the following line to /etc/cups/cupsd.conf in CentOS 4, 5, or 6, or to /etc/cups/cups-files.conf in CentOS 7 and 8. FileDevice yes Restart the CUPS service. service cups restart Use a command akin …

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Inodes received 32-bit numbers or less under older XFS behavior, which always allocated inodes within the first 1TiB of the filesystem. With more recent XFS behavior, inode64 is the default mount option, allowing inodes to be put anywhere inside the filesystem. However, files with inode numbers greater than 32 bits may be difficult for 32-bit …

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To set up the hardware error reporting rasdaemon. Install the rasdaemon package first. Launch the rasdaemon service after enabling data collection in Rasdaemon. Configure the rasdaemon service to restart automatically when the computer boots up. The motherboard DIMM labels can be imported into the EDAC drivers once the service has been launched for simpler fault …

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The idmap sss module has some restrictions when used with CentOS 7. As a result, it is currently not advised to utilize the idmap sss module for Samba file servers registered with AD domains. If you are configuring a CentOS 8 or above version, you must run the following command. The system must be rebooted …

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