the secure shell (SSH) daemon

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42
votes
1answer
48k views

How does tcp-keepalive work in ssh?

I am trying to code a shell-script that uses a ssh-connection for doing "heartbeats". I want to terminate the client- and server-side of that connection after a certain timeout (after the connection ...
7
votes
4answers
3k views

How to debug SSH port forwarding

This is an extension to ssh port forward to access my home machine from anywhere I tried things mentioned there but I am not able to ssh to my machine. Netgear router settings for port forwarding: ...
9
votes
1answer
24k views

Installing fail2ban on CentOS 7

I am using @GarethTheRed 's answer to this question to install fail2ban on a remote CentOS 7 server. I am able to complete all the steps up until tail -f /var/log/fail2ban.log, at which point I get ...
11
votes
5answers
75k views

X client forwarded over SSH “cannot open display: localhost:11.0”

I have enabled X forwarding on remote machine where SSH server is running: # grep -i forward /etc/ssh/sshd_config X11Forwarding yes # On local machine, I have started SSH client with -X flag ...
3
votes
1answer
509 views

Is there a way to run a privileged command upon successful SSH login (not necessarily with shell or PTY)?

I'd like to run a privileged command upon successful SSH logins at the server's end. However, this has to be in the server configuration (sshd_config or anything else that cannot be manipulated or ...
23
votes
6answers
60k views

Where are my sshd logs?

I can't find my sshd logs in the standard places. What I've tried: Not in /var/log/auth.log Not in /var/log/secure Did a system search for 'auth.log' and found nothing I've set /etc/ssh/sshd_config ...
4
votes
1answer
3k views

How to use ssh over http or https?

I have a linux fedora21 client laptop behind a corporate firewall (which lets through http and https ports but not ssh 22) and I have a linux fedora21 server at home behind my own router. Browsing ...
12
votes
2answers
2k views

tmux session killed when disconnecting from ssh

Summary: I'm trying to figure out why my tmux session dies when I disconnect from ssh Details: I have tmux installed on an Arch Linux system. When I start a tmux session I can detach from it and ...
11
votes
2answers
13k views

Why does sshd requires an absolute path?

Why does sshd require an absolute path when restarting, e.g /usr/sbin/sshd rather than sshd Are there any security implications? P.S the error message: # sshd sshd re-exec requires execution with ...
4
votes
3answers
7k views

Authentication refused: bad ownership or modes for file /var/git/.ssh/authorized_keys [duplicate]

EDIT The issue as exposed here is solved (about files modes of the .ssh folder. But an other issue persists so I create a new question : > Unable to login with SSH-RSA key I can no longer ...
4
votes
1answer
10k views

Activity Logging Level in SFTP

I'm using CentOS, i have already figured out how to enable the SFTP Logging. After that when i test it by using FileZilla (from User-end) and tail -f /var/log/sftp.log from the Server, all the ...
4
votes
1answer
658 views

Executing a remote command on SSH connection, before login

I am trying to find a way to execute a specific command when connecting to a server via SSH. By this I mean, the command will execute unconditionally on opening a connection, so this would preferably ...
3
votes
3answers
19k views

sshd_config MaxSessions parameter

I have problem with "MaxSessions" parameter in sshd. I would like to restrict number of sessions via one ssh connection. For example for tcp forwarding. When I set MaxSessions to 0, logons are not ...
6
votes
4answers
4k views

How to setup password-less ssh with RSA keys

I am trying to setup a password-less SSH configuration between two machines and I am having a problem. There are a ton of howtos out there that I have followed and have had no success. Here are the ...
5
votes
2answers
3k views

ssh-add -D doesn't erase stored keys from the ssh-agent

How come this happens?: stan@tcpc:~/.ssh$ ssh-add -l 8192 e0:45:5e:cc:45:3e:17:2b:a6:54:6f:8d:53:1b:j2:e3 github (RSA) 2048 25:41:53:a6:45:5d:ac:eb:5c:45:f8:ce:42:a9:he:aa BITBUCKET (RSA) ...
4
votes
3answers
4k views

How to start SSH daemon on boot on Linux Mint Debian v2

I'm using Linux Mint Debian v2, 64-bit. I noticed recently that my ssh daemon does not start automatically on boot. It used to. I'm not sure if it had to do with my UFW configuration or sshd_config ...
3
votes
2answers
42 views

How to make ssh account capabele to only sshfs and rsync?

I'd like to make ssh account that is capable of doing two things: mounting (can be one) directory via sshfs performing backup&recovery of his/her desired directories using rsync I would love ...
1
vote
1answer
106 views

Being Prompted for Password After Already Registered Public Key On server

NOTE: This is not a duplicate to the popular question. Why am I still getting a password prompt with ssh with public key authentication? I had an original post but I did not get much answers helping ...
1
vote
1answer
4k views

CentOS 7 - ssh login is refused when i use ssh public key, but only works with username password [closed]

I am not able to login via SSH key. I place my id_rsa.pub key in the /root/.ssh/authorized_keys [root@s .ssh]# ll total 4 -rw------- 1 root root 403 Jun 8 00:44 authorized_keys [root@s ~]# cat ...
1
vote
1answer
254 views

SSH slow after configuring TCP Wrappers

We have SSH open on one of our production servers leaving it prone to various brute force attacks to break in. I reduced the attempts by changing the default port from 22. I want to further harden ...
0
votes
2answers
293 views

Unable to login with SSH-RSA key

This post is following this question : Authentication refused: bad ownership or modes for file /var/git/.ssh/authorized_keys . The issue as exposed there is solved (about files modes of the ...
0
votes
0answers
270 views

ssh with rsa key asks for password

I have a server with Ubuntu 14.04 x64 operation system. Part of my sshd_config file (entire file): Port 2202 Protocol 2 PermitRootLogin without-password StrictModes yes RSAAuthentication yes ...
0
votes
2answers
237 views

How to test that X11Forward is working or not?

X11Forwarding yes was enabled and sshd reloaded. But how can I test that X Forwarding works or not? xclock is not installed. Perl and python-base is installed, are there any tricks ex.: pop-up a GUI ...