• efibootmgr: option requires an argument -- 'd' efibootmgr version 15 grub-install.real: error: efibootmgr failed to register the boot entry: Operation not permitted.


    This sometimes happens when trying to install the EFIversion of grub to a device when you are booted into Legacy/MBR mode. It doesn't seem to occur on all machines, but some and seems somewhat BIOS dependent. grub-install --target=x86_64-efi /dev/sda Installing for x86_64-efi platform. grub-install.real: warning: Couldn't find physical volume `(null)'. Some modules may be missing from core image.. grub-install.real: warning: Couldn't find physica........
  • How to allow SSH root user access in Linux/Debian/Mint/RHEL/Ubuntu/CentOS


    A lot of newer installs will automatically prohibit the root user from logging in directly, for security reasons or they will only allow key based access. If you know what you are doing/don't care about security or have an incredibly secure password for testing, then you can enable it. Edit this file: /etc/ssh/sshd_config Find the following line: PermitRootLogin Set it like this: PermitRootLogin yes Now rest........
  • how to use ifplugd in Linux to execute a command or script when a NIC cable is unplugged or plugged in


    It is fairly simple to use once you know how to use it. However, the tricky thing is that by default it doesn't seem to be active or listen on any interface on manually specified. How To Install ifplugd First we install ifplugd sudo apt install ifplugd Let's enable it on our desired device(s) vi /etc/default/ifplugd set this line as so:........
  • Debian 9 SSH root password authentication failure password not working problem / solution


    In Debian a lot of times SSH disables the root user to login by password by default. This means you will get an authentication failure as if you typed in the wrong password. The logs also indicate the password is wrong but what is often the case is in the config file Check /etc/ssh/sshd_config cat /etc/ssh/sshd_config|grep -i permitrootlogin Make sure it says: PermitRootLogin yes If not change it and restart SSH........
  • OpenVPN error ERROR: Cannot ioctl TUNSETIFF tun: Operation not permitted (errno=1)


    This basically means that you are running as non-root and you need to be root to create the tun0 or tap0 device on OpenVPN. You could try sudo or adding the openvpn binary to the list of sudoers.........
  • Track 01: 34 of 1726 MB written (fifo 100%) [buf 99%] 3.6x.Errno: 5 (Input/output error), write_g1 scsi sendcmd: cmd timeout after 1.897 (40) s CDB: 2A 00 00 00 44 A9 00 00 1F 00 resid: 6144 cmd finished after 1.897s timeout 40s write track da


    These errors believe it or not are simply because of not being the root user or running with sudo! However if you didn't know to try as root you'd think there was a problem with your burner or disc Essentially it looks like without root you cannot send the required scsi commands to continue writing. Ithink cdrecord should have built-in tests or safeguards to see if it has the permissions to run the required commands. I guess for more advanced users the idea is simila........
  • The connection was reset The connection to the server was reset while the page was loading.


    In Firefox I cannot connect to any website, proxy is disabled and outside network access is confirmed, no system or manual proxy was set on this Linux Mint/Ubuntu system. Normally this can be caused by proxy or DNS problems and the weird thing is that traceroute and ping to other IPs worked fine but even connecting to sites by IP was not working. The connection was reset The connection to the server was reset while the page was loading.........
  • Setting Ulimit


    I never found a solution to do it live (nothing worked that I found) so it looks like a relogin is required. Check your maximum file limit cat /proc/sys/fs/file-max 824460 This is different than your actual's user limit which you'll see below ulimit -n 1024 Try and set it higher but it won't work ulimit -n 65000........
  • Asterisk iptables block bruteforce attacks howto with fail2ban


    yum -y install fail2ban vi /etc/fail2ban/jail.conf [asterisk-tcp] enabled = true filter = asterisk action = iptables-multiport[name=asterisk-tcp, port="5060,5061", protocol=tcp] sendmail-whois[name=Asterisk, dest=you@example.com, sender=fail2ban@example.com] logpath = /var/log/asterisk/messages maxret........
  • open /dev/kvm: No such file or directory failed to initialize KVM: Operation not permitted - Solution


    open /dev/kvm: No such file or directory failed to initialize KVM: Operation not permitted [ 96.084502] kvm: disabled by bios Any of the above means that "Virtualization" is not enabled in your BIOS. Most servers and Desktops (non-mainstream) can do this no problem but leave it off by default. Note that some systems even though the CPU supports it, don't allow enabling of Virtualization for some reason (especially some lap........
  • ioctl: Operation not permitted can't delete tunnel


    When trying to delete a tunnel ip tunnel del tunl0 I get this message: ioctl: Operation not permitted........
  • How To Burn ISO Image using cdrtools/dvdrtools for Linux/Unix Ubuntu/Debian/RHEL/Centos etc..


    It really is as simple as: cdrecord -v dev=/dev/sr0 pathtoyourisoimage.iso -v is for verbose, I prefer it but if you don't you won't see as much output like below (I like to know the details and exactly what's happening) dev=/dev/sr0 specifies the device name of your burner (they say not to use it and to specify some weird annoying device string but using the raw /dev has always worked for me and is how it should have been implemented from the start IMHO)........
  • Linux High IOWAIT updatedb can't be killed and crash with mdadm


    high IO wait 424 root 39 19 1900 848 552 D 0.0 0.0 0:00.91 updatedb root 424 0.0 0.0 1900 848 ? DN Mar11 0:00 /usr/bin/updatedb -f sysfs?rootfs?bdev?proc?cpuset?binfmt_misc?debugfs?sockfs?usbfs?pipefs?anon_inodefs?futexfs?tmpfs?inotifyfs?eventp........
  • Postfix Enable SSL/TLS with your certificate


    Create Cert & Key: openssl req -new -x509 -nodes -days 1530 -out server.crt -keyout server.key mkdir /etc/mailssl chmod 700 /etc/mailssl cp server.* /etc/mailssl Postfix SSL config Edit /etc/postfix/main.cf: #SSL stuff smtpd_tls_cert_file = /etc/mailssl/server.crt smtpd_tls_key_file = /etc/mailssl/server.key To make smtps w........
  • Local policy does not permit you to log on interactively. - Solution/Fix


    For a standalone system the solution is simple, just use the same version of Windows a copy a good version of: C:windowsSecurityDatabasesecedit.sdb from another computer. Then you should be able to login again without getting the nasty message "Local policy does not permit you to log on interactively." Of course you will probably need a way of accessing the filesystem off-line in order to get to it such as a Linux boot disc. Some........
  • Linux Burn MP3 CD On the Fly using


    I finally decided to look into some utils that did this, and the first one I found is "mp3burn". It is unbelievable simple and perfect. *2017-11 update and mp3burn is still available in standard repos such as Ubuntu 14/16 so this is a current and working project. Just install the package and it gets all required libraries to convert and then burn's on the fly. And you won't believe how simple it is. I just want to a directory that had the MP3's I wanted t........
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