SSH login without password Your aim. You want to use Linux and OpenSSH to automate your tasks. Therefore you need an automatic login from host A user a to Host B. Telnet Connecting to Remote Up SSH Connecting Securely to Previous Escape sequences Contents sshkeygen passwordless SSH login SSH is often used to login from. You can login to a remote Linux server without entering password in 3 simple steps using sskykeygen and sshcopyid as explained in this article. Unix Toolbox. Unix Toolbox. This document is a collection of UnixLinuxBSD commands and tasks which are useful for IT work or for advanced users. This is a practical guide with concise explanations, however the reader is supposed to know what she is doing. Hardware Statistics Users Limits Runlevels root password Compile kernel Repair grub Misc. Running kernel and system information. Get the kernel version and BSD version. Full release info of any LSB distribution. Su. SE release Get Su. Screenshot-2016-04-11-20-18-19.png' alt='Fingerprint Keygen' title='Fingerprint Keygen' />SE version. Get Debian version. Use etcDISTR release with DISTR lsb Ubuntu, redhat, gentoo, mandrake, sun Solaris, and so on. See also etcissue. Show how long the system has been running load. Award Corporate Program : Free Programs, Utilities And Apps. Display the IP address of the host. Linux only. man hier Description of the file system hierarchy. Show system reboot history. Hardware Informations. Kernel detected hardware. Detected hardware and boot messages. Read BIOSLinux cat proccpuinfo CPU model. SSHKEYGEN1 BSD General Commands Manual SSHKEYGEN1 NAME top sshkeygen authentication key generation, management and conversion. So sshkeygen R hostname is a nice syntax as you even do not have to provide the file name and path for knownhosts and it works with hashed names. Explains what the SSH key fingerprint is and how its used. If you have a Microsoft Fingerprint Reader, Microsoft will tell you that it wont work with Windows 7. If you try to install the driver software anyway, Windows. Hardware memory. grep Mem. Total procmeminfo Display the physical memory. Watch changeable interrupts continuously. Used and free memory m for MB. Configured devices. Show PCI devices. Show USB devices. Show a list of all devices with their properties. Show DMISMBIOS hw info from the BIOSFree. BSD sysctl hw. model CPU model. Gives a lot of hardware information. CPUs installed. sysctl vm Memory usage. Hardware memory. sysctl a grep mem Kernel memory settings and info. Configured devices. Show PCI devices. Show USB devices. Show ATA devices. Show SCSI devices. Load, statistics and messages. The following commands are useful to find out what is going on on the system. IO statistics 2 s intervals. BSD summary of system statistics 1 s intervals. BSD tcp connections try also ip. BSD active network connections. BSD network traffic through active interfaces. BSD CPU and and disk throughput. System V interprocess. Last 5. 00 kernelsyslog messages. System warnings messages see syslog. Users id Show the active user id with login and group. Show last logins on the system. Show who is logged on the system. Add group admin and user colin LinuxSolaris. Colin Barschel g admin m colin. G lt group lt user Add existing user to group Debian. A lt user lt group Add existing user to group Su. SE. userdel colin Delete user colin LinuxSolaris. Free. BSD add user joe interactive. Free. BSD delete user joe interactive. Use pw on Free. BSD. Add a new member to a group. Colin Barschel g admin m s bintcsh. Encrypted passwords are stored in etcshadow for Linux and Solaris and etcmaster. Free. BSD. If the master. To temporarily prevent logins system wide for all users but root use nologin. The message in nologin will be displayed might not work with ssh pre shared keys. Sorry no login now etcnologin Linux. Sorry no login now varrunnologin Free. BSDLimits. Some application require higher limits on open files and sockets like a proxy. The default limits are usually too low. Linux. Per shellscript. The shell limits are governed by ulimit. The status is checked. For example to change the open files limit from. This is only valid within the shell. The ulimit command can be used in a script to change the limits for the script only. Per userprocess. Login users and applications can be configured in etcsecuritylimits. For example. cat etcsecuritylimits. Limit user processes. Limit application open files. System wide. Kernel limits are set with sysctl. Permanent limits are set in etcsysctl. View all system limits. View max open files limit. Change max open files limit. Permanent entry in sysctl. How many file descriptors are in use. Free. BSDPer shellscript. Use the command limits in csh or tcsh or as in Linux, use ulimit in an sh or bash shell. Per userprocess. The default limits on login are set in etclogin. An unlimited value is still limited by the system maximal value. Kernel limits are also set with sysctl. Permanent limits are set in etcsysctl. The syntax is the same as Linux but the keys are different. View all system limits. XXXX maximum number of file descriptors. Permanent entry in etcsysctl. Typical values for Squid. TCP queue. Better for apachesendmail. How many file descriptors are in use. How many open sockets are in use. Default is 1. 02. See The Free. BSD handbook Chapter 1. And also Free. BSD performance tuninghttp serverfault. Solaris. The following values in etcsystem will increase the maximum file descriptors per proc. Hard limit on file descriptors for a single proc. Soft limit on file descriptors for a single proc. Runlevels. Linux. Once booted, the kernel starts init which then starts rc which starts all scripts belonging to a runlevel. The scripts are stored in etcinit. N. d with N the runlevel number. The default runlevel is configured in etcinittab. It is usually 3 or 5. The actual runlevel can be changed with init. For example to go from 3 to 5. Enters runlevel 5. Shutdown and halt. Single User mode also S2       Multi user without network. Multi user with network. Multi user with X6       Reboot. Use chkconfig to configure the programs that will be started at boot in a runlevel. List all init scripts. Report the status of sshd. Configure sshd for levels 3 and 5. Disable sshd for all runlevels. Debian and Debian based distributions like Ubuntu or Knoppix use the command update rc. Default is to start in 2,3,4 and 5 and shutdown in 0,1 and 6. Activate sshd with the default runlevels. With explicit arguments. Disable sshd for all runlevels. Shutdown and halt the system. Free. BSD. The BSD boot approach is different from the Sys. V, there are no runlevels. The final boot state single user, with or without X is configured in etcttys. All OS scripts are located in etcrc. The activation of the service is configured in etcrc. The default behavior is configured in etcdefaultsrc. The scripts responds at least to startstopstatus. Go into single user mode. Go back to multi user mode. Shutdown and halt the system. Reboot. The process init can also be used to reach one of the following states level. For example init 6 for reboot. Halt and turn the power off signal USR21       Go to single user mode signal TERM6       Reboot the machine signal INTc       Block further logins signal TSTPq       Rescan the ttys5 file signal HUPWindows. Start and stop a service with either the service name or service description shown in the Services Control Panel as follows. WSearch. net start WSearch start search service. Windows Search. net start Windows Search same as above using descr. Reset root password. Linux method 1. At the boot loader lilo or grub, enter the following boot option. The kernel will mount the root partition and init will start the bourne shell. Use the command passwd at the prompt to change the password and then reboot. Forget the single user mode as you need the password for that. If, after booting, the root partition is mounted read only, remount it rw. Free. BSD method 1. On Free. BSD, boot in single user mode, remount rw and use passwd. You can select the single user mode on the boot menu option 4 which is displayed for 1. The single user mode will give you a root shell on the partition. Unixes and Free. BSD and Linux method 2. Other Unixes might not let you go away with the simple init trick. The SSH SFTP Key Fingerprint And Its Role In Server Authentication. The first time a user connects to your SSH or SFTP server, hisher file transfer client may display an alert or notice indicating it doesnt recognize the servers fingerprint. What its actually referring to is the servers SSHSFTP key fingerprint, an important security feature that helps users and client applications authenticate SSHSFTP servers. This post explains how its used. Importance of server authentication. Server authentication is a process that allows client applications to validate a servers identity. In other words, it helps a client determine whether its really connecting to the server it intended to connect to. If the server fails the authentication process, then its possible that the servers host key was simply changed by the admin. Thats not a big problem. Tutorial Pic Basic Pro Pdf there. However, it could also mean that someone has carried out a spoofing or man in the middle attack and, therefore, the client is likely on the verge of connecting to a malicious server. Now, THAT is a serious problem. If a user unknowingly logs in to a malicious server, who ever has control of that server could easily acquire that users login credentials and then use those credentials to gain access to the legitimate server. Secondly, if the unwitting user uploads files to the malicious server, those files will surely fall into the wrong hands. Lastly, if a user downloads files from the server, that user could end up downloading malware. Server authentication helps prevent these from happening because if the authentication process fails, the client will be given an appropriate warning. SSH SFTP server autentication using fingerprints. How do you implement server authentication in SSHSFTP Theoretically, you can do this. As a server admin, you can furnish each user a copy of your servers public key. Public keys are supposed to be unique. Everytime a user connects to the server, the server can show the user its public key and the user can then compare that with his local copy. If they match, the user knows hes connecting to the right server. There is however one problem with this method. Public keys are quite lengthy. So lengthy that it would be impractical for anyone to manually compare two copies. Your server authentication process will be time consuming. A better way of carrying out server authentication when using SSHSFTP is by inspecting the public key fingerprint. A fingerprint in this context is basically a hash function of a public key. Simply put, its a shorter equivalent of the public key. If youre not familiar with how hashes work, I suggest you read the post Understanding Hashing first. Because fingerprints are much shorter than public keys, theyre also much easier to inspect and compare even through the naked eye. How to use public key fingerprints. The first time a user connects to your SSHSFTP server, hell be presented with your servers fingerprint. To verify, the user can contact you and you can then dictate to him your record of the fingerprint. If they match, the user can then store that fingerprint for future login sessions. Most SSHSFTP clients allow users to save fingerprints. Once a fingerprint is saved, the client can automatically look up that fingerprint every time it connects to an SFTP server. If a match is made, the client will know its connecting to a server it had already connected to before. Its therefore very important to make sure all fingerprints the client saves have already been manually verified. If you accept a fingerprint without verifying, especially if youre connecting to a remote server, you might end up storing a fingerprint of a malicious server. How to obtain the fingerprint if youre an administrator. K9 Web Protection Full Crack'>K9 Web Protection Full Crack. What if youre an admin but dont know what your servers fingerprint isDont look so surprised. These things happen you know. The quickest way to obtain it would be to login to your SSHSFTP server from a locally installed client application, i. That way, you can be absolutely sure youre safe from man in the middle attacks. If youre using Linux and have the built in SSH client, make sure there is no localhost entry found inside . Delete the entry if you find any before attempting the connection. The moment you connect, youll encounter something like this Copy that fingerprint and save it where you can easily access it. If your server runs on Windows or another GUI based operating system, then you can install an SFTP client like Any. Client and connect to the server again, locally. You should then see something like this Lastly, if this tool is available on your server its usually available on Linux, you may run the following command ssh keygen lf pathtopublickeypubkeyinopensshformat. In some SFTP servers, youll have to export the public key in Open. SSH format for this to work. In JSCAPE MFT Server, go to Server Key Manager Server Keys. Select the server key, click Export Public key. Select the Open. SSH format and then click OK. Once the public key is exported, you can then run ssh keygen lf on it likeso to reveal the fingerprint Related posts.