OpenVPN: certificate is not yet valid
When OpenVPN authentication process fails during a connection attempt with an error message like 'certificate is not yet vaild', check the date of your machine. According to a web source, it is required to have synchronized time between VPN server and client.
Correct time OpenVPN requires client and server to have more or less synchronized time. Therefore make sure that router has correct time. To check it use command date and if you get info about year 1970, you should enable NTP client. Also, ntp server has to be outside of your VPN as time should be corrected before VPN is established. If you have syslog enabled (to local server, or the server outside your VPN), errors like TLS Error: Unroutable control packet received from server_ip:1194 may indicate this problem. (This error message may appear if your certificates are not valid or have expired, too.) If you get an error message saying that your certificate is not yet valid, set the dd-wrt clock to UTC time (in the first configuration page).
To synchronize time, you can use ntpdate tool:
# ntpdate pool.ntp.org
References
- http://www.dd-wrt.com/wiki/index.php/OpenVPN
- http://www.justin.my/2011/04/how-to-synchronize-date-and-time-in-linux-console/
Linux Mint: Can't change my laptop's screen brightness!
Edit /etc/default/grub and add acpi_osi, acpi_backlight options.
GRUB_CMDLINE_LINUX_DEFAULT="i915.modeset=1 acpi_osi= acpi_backlight=vendor"
Also checkout the kernel parameters under /sys/class/backlight/
References
문서를 돈주고 출력했는데 깜빡하고 프린터기를 안켰다?
등본과 같은 공적 문서나 학적기록 등을 결제하고 출력하였으나 정작 프린터는 꺼져있을때, 돈은 먹었고 프린트는 안되고 어찌한담?
이럴때는 프린터처럼 생긴 트레이 아이콘을 누르면 출력하고자 했던 문서가 출력 대기중인 문서로 남아있다. 이 문서의 임시파일을 찾아서 PDF와 같은 포멧으로 변환시켜주면 된다.
문서의 임시 파일의 위치는 다음과 같다:
%SystemRoot%\SYSTEM32\SPOOL\PRINTERS
탐색기로 열어서 대기중의 문서의 시간과 .SPL확장자로 끝나는 파일의 시간을 이용하여 문서를 찾고 해당 파일을 다른 폴더에 복사한 후 SPLViewer와 같은 프로그램으로 열어어서 PDF로 변환해주면 된다.
References
리눅스 민트(우분투) 데스크톱 환경에서 한/영키를 누를때 Alt키가 같이 눌린다?
Linux Mint(Ubuntu): Hangul key is also Alt key?
아래 명령을 루트 유저로 실행:
Try this command as root user:
# xmodmap -e 'remove mod1 = Hangul'
자동 시작 스크립트 만들기; Make startup script
/etc/init.d/fix_hangul_key.sh:
#!/bin/bash xmodmap -e 'remove mod1 = Hangul'
# chmod 755 /etc/init.d/fix_hangul_key.sh
# update-rc.d -f fix_hangul_key.sh defaults
노트: update-rc.d 시스템 명령은 최신버전의 우분투 환경에서 동작하지 않을 수 있습니다.
Note: update-rc.d may not working with latest version of Ubuntu.
Linux Mint: System is very slow!
It's caused by drm_kms_helper and I don't know what it is.
First, upgrade your system(apt-get update && apt-get upgrade && apt-get dist-upgrade) including kernel.
To disable it:
# echo N > /sys/module/drm_kms_helper/parameters/poll # echo "options drm_kms_helper poll=N">/etc/modprobe.d/local.conf
To disable at start up, add below script to /etc/init.d/ and add using update-rc.d.
/etc/init.d/disable-krm_kms_helper.sh:
#/bin/bash echo N> /sys/module/drm_kms_helper/parameters/poll
# update-rc.d -f disable-krm_kms_helper.sh defaults
After awhile, somehow the lags are gone away.
References
https://bugs.launchpad.net/linuxmint/+bug/1122219Linux Mint: Things to customize after initial install
- Edit /etc/apt/sources.list to your local mirror - Add your country code(e.g KR for South Korea) to URLs
- Upgrade system using apt-get update && apt-get upgrade && apt-get dist-upgrade
- Install language support from system menu 'lanauge support' and install ibus to toggle between languages. - ibus and ibus-korean for korean users
- If system is very slow, disable drm_kms_helper - see this post
References
http://fineday2love.tistory.com/86iptables: Set rules to make firewall acts like a home routers.
Home routers accept connections established from inside and deny incoming connections that isn't
Initialize iptables rules:
# iptables -F # iptables -X # iptables -Z
Set default chain policies:
# iptables -P INPUT DROP # iptables -P FORWARD DROP # iptables -P OUTPUT ACCEPT
Accept on localhost:
# iptables -A INPUT -i lo -j ACCEPT # iptables -A OUTPUT -o lo -j ACCEPT
Allow established sessions to receive traffic:
# iptables -A INPUT -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT
Save rules:
# iptables-save
References
http://superuser.com/questions/427458/deny-all-incoming-connections-with-iptables http://blog.daum.net/hypermax/6Linux Mint: MATE vs Cinnamon
Re: MATE vs. Cinnamon, which is more likely to continue? by passerby on Tue Feb 26, 2013 5:57 pm From what I've seen/experienced, Cinnamon's development is more active than MATE's. MATE is faster, lighter, more stable, etc. for the time being, but appears to be a smaller project overall. Cinnamon has problems in virtualbox that don't exist on a normal machine. You might want to try a live boot; it'll be slower than an actual install, but it'll give you a better feel for the environmen
I'm currently using Linux Cinnamon 14. I had issues connect WiFi while using wired network and Cinnamon has better UI.
Linux Mint 13 "Maya" is LTS(Long term support release), supported until April 2017.
Power button to suspend a Ubuntu desktop
I want to suspend the machine when I press the power button. I'm using Linux Mint and it's based on Ubuntu so it's same.
Install dconf-tools: sudo apt-get install dconf-tools Press alt+f2 and open dconf-editor (or in a terminal type dconf-editor) Navigate to org.gnome.settings-daemon.plugins.power and set your default button-power action there:
Even though the option is already set for your desired option, click the option and mark as modified(blod).
orThis is the quick, simple answer I needed:# gsettings set org.gnome.settings-daemon.plugins.power button-power 'hibernate'If you want to see your settings first, try this:# gsettings list-recursively org.gnome.settings-daemon.plugins.power
After edit dconf options, restart the machine.
How to mount linux ramdisk
You should use tmpfs for that instead.mount -t tmpfs -o size=10g none /mnt/point
HDD S.M.A.R.T Value Test from Linux Console / Find out each HDD's serial number
The package name for smartctl is smartmontools
# apt-get install smartmontools
It's really simple
# smartctl -H /dev/sda
To find out each hdd's serial number, use hdparm
# hdparm -I /dev/sda
Steam.exe (mail exception): ERROR: copying steamNEW.exe to Steam.exe failed
When you got this error message when you're trying to run Steam.
Steam.exe (mail exception): ERROR: copying steamNEW.exe to Steam.exe failed, Win32 Error 32 "The process cannot access the file because it is being used by another process."
Try to run Steam.exe or SteamNew.exe as Administrator account. (right click it and click 'run as administrator'. It's in your steam directory)
Firefox ssh SOCKS 5 tunneling is too slow!
Firefox is the best browser for surf the web through proxy connection. it supports independent proxy environment. not like Chrome browser and Internet Explorer. (Chrome inherits Internet Explorer's proxy settings.) Basically Firefox has it's own proxy function in it.
Few days ago, I wanted to surf the web through my server but It seemed something went wrong, tunneling connection was very slow and even ssh terminal was not responding while trying to connect a website. this problem could be caused by ssh connection or Firefox. I set the SOCKS 5 proxy for Internet Explorer for test and it was working fine. so I figured that ssh connection wasn't the problem.
The problem was Firefox. I installed many plugins and extensions after many years of usage. proxy function was gliched somehow.
To fix the problem, simply you can Reset your Firefox browser. before you do that, make sure you have backups for bookmarks, plugin list, etc..
Alt-H -> Troubleshooting Information -> Reset Firefox
References
sshfs - Can't kill a disconnected process
I'm using sshfs through forward ssh tunnel connection and got disconnected unexpectly.
Note: Using sshfs through ssh tunneling connection is such a way to wasting computer power because it encrypts data double times. First, the tunnel connection, Second, sshfs connection itself. However if you're using encfs, there's not much of an options are available. I think this is the easy and best way to mount a encrypted directory point made by encfs(other users can't even access the encrypted directory. not even root.) other options like NFS requires root access with some tricks.
The problem was:
- I couldn't see my home directory(ls -al command hangs) - where the sshfs mounting point directory was located.
- command df -sh hangs too.
My home directory is /home/myhome/(for example.) and the mounting point was /home/myhome/sshfsdir. It seemed like every I/O processes that access my home directory(which is /home/myhome/) hangs due to unable to read the one of child nodes. mounting point directory /home/myhome/sshfsdir/ was one of them.
However I was able to access the / directory as root user(probably any user too), I was able to un-mount sshfs mounting point using fusermount command with the lazy option -z.
# fusermount -uz /home/myhome/sshfsdir/
Then I checked sshfs process(ps -ef | grep sshfs). there was still one sshfs process hangs under the background. I couldn't kill it by kill PID command. so I googled.
If a sshfs process keep hangs under the background on your system or any other processes that you can't kill, try to use the option -KILL for kill command.
# kill -KILL PID
I've seen this when I drop a connection to an active screen then reconnect. The linked bug describes the problem as I see it. What appears to happen is that screen is trying to notify the tty that holds it that it is about to leave, but since the tty is hung due to a dropped connection it has to wait for the timeout to happen (which is upwards of five minutes in some cases). To fix it, I do this: figure out which tty is holding on to the screen session ps -ef | grep screen | grep pty find the login bash that is associated with that tty ps -ef | grep bash | grep $PTY kill that bash kill -KILL $PID This causes screen to complete its disconnect correctly, and lets you reconnect normally. See here for an example script automating this somewhat.
I found a wiki article that explains this problem softly:
killing me softly
or, how to be as gentle as possible when killing a Linux/Unix process
I recommend kills in this order, with a short delay between each:
- kill -TERM (same as kill without an argument)
- kill -HUP (same as closing the window)
- kill -INT (same as Ctrl-C)
- kill -QUIT (same as Ctrl-\)
- kill -PIPE (same as quitting the program you've piped it into, e.g. less)
- kill -KILL (a.k.a. -9)
The only thing that can ignore a KILL signal is I/O. If your process still won't die when you use KILL, there is often no option but to reboot the system. This is one of my pet peeves about Linux.
Template
Here's a bash function to do the job:
kill_softly() { for sig in TERM HUP INT QUIT PIPE KILL; do echo "kill -$sig $@" if ! kill -$sig "$@"; then # the kill command failed - this usually means that the process is now dead break fi sleep 2 done }
Lookup a phone number to determine carrior company to send SMS via E-mail
Phone number lookup site: http://www.fonefinder.net
SMS Gateway list: http://basicstate.com/htm/page.htm
Once you find out the carrior compnay then you can send SMS messaged via E-mail.
Add sudoers
Instead of editing /etc/sudoers, you can add a user to sudoers by adding the user to the group 'sudo'.
For example:
# usermod -a -G sudo user
Linux add/remove an existing user to a gorup
Add an existing user to a group
# usermod -a -G GROUP USER
Remove an existing user form a group
# gpasswd -d USER GROUPhttp://www.howtogeek.com/50787/add-a-user-to-a-group-or-second-group-on-linux/ http://unix.stackexchange.com/questions/29570/how-do-i-remove-a-user-from-a-group
encfs - fuse: failed to open /dev/fuse: Permission denied
encfs - fuse: failed to open /dev/fuse: Permission denied
That group may not be present for the current shell session. Just do the following.grepto see the list of groups in which the user has been added. To take effect, you may have to logout and login again. Or it would take effect after the next reboot./etc/groups
chmod 660 /dev/fuse