How to disable the reverse DNS lookup by the SSD server on Linux? To turn off reverse DNS lookups of the SSH daemon, log on the server and add UseDNS no to /etc/ssh/sshd_config. And remember to restart the sshd service by service sshd restart or systemctl restart sshd.service or other commands depending on your system.
I would like to check whether the domain name’s IP has changed in the authoritative DNS server. The system’s configured DNS server may still cache the old IP, which is fine. The question is how to query from the authoritative DNS server the new IP? You can use dig – DNS lookup utility to query…
Can I get a non-self-assigned and free Web server SSL/TLS certificates for my https websites? Asking the users to accept the self-assigned SSL certificates for my websites is not very convenient. Please check https://letsencrypt.org/ . PS: StartSSL used to provide 1 year free SSL. But StartCom CA is closed since Jan. 1st, 2018.
I can only connect to a Linux server by SSH. How to check whether a USB disk is connected to the Linux server? 2 ways I usuaully use: Method One: Check the print out of dmesg After the USB storage is connected and detected by Linux, it may print some messages containing “[sde]” (the new…
Currently, I need to integrate MySQL client into SQLE as SQLE’s client. And then, we just need design/implement a translation layer to transfer MySQL protocol into SQLE engine part (KV+ internal exactly). Mysql-Proxy could solve this problem but it is complex to be only a MySQL server. Therefore, I remoduled MySQL-proxy to be more simple…
Managing a cluster of servers, I would like to notified when a server is started. How to make the Linux servers email me or other admins automatically after they are started? I did this by adding a crontab entry on each servers like @reboot date | mailx -S smtp=smtp://smtp.example.com -s “`hostname` started” -r zma@example.com zma@example.com…
After a kernel panic, it is impossible to remotely connect to the Linux server to reboot it by SSH. How to make the panic kernel automatically reboot itself? Linux kernel has a nice feature that reboots itself after a timeout when a kernel panic happened. Usually, it is disabled by default. To turn it on,…
On CentOS 6.6, I find that it can make the screen (console, not X) blank after a while. However, it does not power the screen off. This usually work on Fedora or other releases. I guess this is caused by some configurations specific in CentOS 6.6. How to make CentOS 6.6 power off the console…
Alt key seems not work in xterm. Alt is important for Emacs. How to make Alt key work in xterm? Put this in your ~/.Xresources file: XTerm*eightBitInput: false XTerm*eightBitOutput: true Remember to make it take effect after you change the ~/.Xresource without restarting the X server by xrdb -merge ~/.Xresources
Currently, I have created my branch dev-harry but I cannot pull it successfully as follows. harryxiyou@common_vm ~/forest/kvplus/kvplus $ git branch * dev-harry master rc harryxiyou@common_vm ~/forest/kvplus/kvplus $ git pull You asked me to pull without telling me which branch you want to merge with, and ‘branch.dev-harry.merge’ in your configuration file does not tell me, either….
My Linux distro is Linux Mint 17 (Ubuntu 14.04.1 LTS (Trusty Tahr)). I am using NetworkManager. The old trick does not work: $ cat /etc/resolv.conf # Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8) # DO NOT EDIT THIS FILE BY HAND — YOUR CHANGES WILL BE OVERWRITTEN nameserver 127.0.1.1 If you are using…
A commit is not the HEAD now. and git commit –amend will not work for it. How to change its commit message? You can use git rebase together with git commit –amend as follows. Assume your commit to be edited is 2b8ed. $ git rebase -i 2b8ed^ Change the pick to edit in the line…
We may need to maintain a dev-name branch on git remote server to share your codes. How to create the branch? 1, git checkout -b your_branch_name 2, Do your changes, add commit 3, git push origin your_branch_name References:http://stackoverflow.com/questions/1519006/how-do-you-create-a-remote-git-branch
I want to kick off a user such as “bob” on a Linux box which I managed remotely. How to do this? bob may log on the Linux box by various ways: Log on the screen on the Linux box (locally) with a X server. Log on remotely by a ssh shell. Log on by…
If you encounter an error message like the one below when attempting to SSH to a server: @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ @ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @ @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY! Someone could be eavesdropping on you right now (man-in-the-middle attack)! It is also possible that a host key has…
When use gitbook to generate ebook, Calibre reports this: RuntimeError: X server required. If you are running on a headless machine, use xvfb After xvfb is installed, it does not work either. How to make gitbook/Calibre work on a headless server? You need to wrap the command ebook-convert with xvfb-run. However, in gitbook (lib/generate/ebook/index.js), ebook-convert…
We set up Xen F19 VMs on a Xen 3.4.3 / 2.6.32.13 xenified kernel. Check here.). However, we find the Xen VM keeps reporting: kernel netfront: Too many frags and skb rides the rocket in the dmsg. This solves the problem (assume in physical server vif1.0 is for the eth0 on the VM): On the…
offlineimap actually does “synchronization”—if an email is deleted from the server, the email will be deleted from the local Maildir (http://offlineimap.org). This is good for mail sync. However, for backing up emails,one would like to keep the email even if it is deleted from the server. How to achieve this? You may use `getmail` which…
The question is as follows. harry@debian:~/workshop1/qemu_test/version1/test$ qemu-system-x86_64 -hda qcow2.img -cdrom domU-x86_64-FS.img -boot d -m 1024 VNC server running on `::1:5900′ harry@debian:~/workshop1/qemu_test/version1/test$ vncviewer 127.0.0.1:1 vncviewer: ConnectToTcpAddr: connect: Connection refused Unable to connect to VNC server Solution (add -vnc parameter for qemu-system-x86_64): harry@debian:~/workshop1/qemu_test/version1/test$ qemu-system-x86_64 -hda qcow2.img -cdrom domU-x86_64-FS.img -boot d -m 1024 -vnc 127.0.0.1:2 harry@debian:~/workshop1/qemu_test/version1/test$ vncviewer 127.0.0.1:2…
How to install WordPress Buddy Press template? Themes for BuddyPress are available at:http://wordpress.org/extend/themes/tags/buddypress Make sure that the theme tagged as “buddypress” is compatible with the BP/WP version activated in your server. As of BuddyPress 1.7, BuddyPress works with most any WordPress out of the box. BuddyPress 1.7 includes base template files that should fit into…