Questions tagged [sshd]
the secure shell (SSH) daemon
718
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key type ecdsa-sha2-nistp521 not in PubkeyAcceptedAlgorithms [preauth]
I have trouble setting passwordless authentication on a host:
Sep 21 09:57:36 pvestorage2 sshd[1688625]: userauth_pubkey: key type ecdsa-sha2-nistp521 not in PubkeyAcceptedAlgorithms [preauth]
OS: ...
1
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1
answer
48
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How to configure SSHD to allow users to ssh without password or public key?
I just want to allow one user to be public, i.e. let people log in without typing a password or having to setup a public key. This is to create an open SSH app. It should be simple but it seems to be ...
- 111
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Environment variables are not getting loaded when script is executed on a remote server via SSH (RHEL 8)
I have a vendor script (startup.sh) to start application services on a Linux box. Script when called manually by logging into the server (as sudo su - userID) initiates all the environment variables. ...
- 15
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2
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66
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Reorder of launching Systemd services
OS: Debian 11 Bullseye
Context:
The Zerotier application adds the zerotier-one.service system service and creates a virtual network interface (when it works).
The sshd server default listens to all ...
- 37
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61
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How to restrict user login for specific IP-address (private address)?
I have two users on my ssh-server machine, user_A and user_B. user_B is permitted to log in with private key only for security reasons, because he needs to log in from remote. All this works.
My ...
- 13
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28
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ssh-copy-id closed by remote host
I'm trying to copy public ssh with ssh-copy-id but it gives a connection close:
user@serverA:~/ctm/cm/AFT/data/Keys$ ssh-copy-id -p 1222 -i /home/user/keys/serverA.pub vivek@serverB
/usr/bin/ssh-copy-...
- 23
2
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1
answer
299
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Are all Debian 11 systems automatically vulnerable to CVE-2023-38408?
I really really hope I'm wrong here, but it seems that Debian 11 has a vulnerable version of OpenSSH.
My OpenSSH banner reports my OpenSSH version is:
8.4p1 Debian 5+deb11u1
I checked with sshd and it ...
- 739
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19
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RB5 linux system cannot use ssh to connect V2X with the serial port
I have a V2X module, and I cannot it to linux/window PC with USB. Then using the command ssh [email protected], and entrance the v2x module.root@autotalks:~#
However, when i used the RB5, the ssh root@...
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43
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Use sshfs session to run commands on the remote
Something has happened with the SSH process on a remote server so that now when trying to connect it rants:
kex_exchange_identification: read: Connection reset by peer
It looks like the SSH daemon ...
- 345
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230
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SSH Key issue - Fedora 38
I've a remote server with at least 2 users (root and myself).
I've the same keys in .ssh/authorized_keys in both $HOME folder.
I can connect with the root account, but from my account i've a "...
- 354
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2
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49
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How can I map the sshd logs to my current ssh session?
I am exploring methods to correlate my current SSH session with the SSHD logs.
I aim to extract specific information from the SSHD logs that pertain to my SSH session only.
Jul 04 09:39:06 linuxbox ...
- 123
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37
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sshing with a certificate as root
I seem to have the opposite problem then all the other posts I found during my search. I can log in as root with a password; but, not with a certificate. I followed the same steps I have done dozen ...
- 366
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How to make Ubuntu 22 accept old Putty connections? [duplicate]
I have upgraded from 20 to 22 and now unable to login to it with putty, saying
Couldn't agree a host key algorithm...
I would like to make server backwards compatible, not to upgrade putty. How to ...
- 3,195
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SSH Authentication Prompts Twice for Password When Using PAM with Google Authenticator
I'm setting up two-factor authentication (2FA) on an Ubuntu server using libpam-google-authenticator. I've configured SSH to use PAM for authentication with the following /etc/pam.d/sshd configuration:...
- 11
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Use openssh for ssh connections and for public sftp
I have a system to which some users need to connect trough regular SSH. I will name them the “Privileged Users”.
In the same time this system should provide an SFTP server to “Anonymous” user (without ...
- 1,130
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17
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Why does ssh to a Chromebook now time out after rebooting it?
On a new Chromebook, I:
Enabled the Linux environment.
Configured and started sshd.
Added appropriate authorized_keys.
Was able to ssh in from a Ubuntu machine without a password.
Everything was ...
- 426
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0
answers
180
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Very odd SSH known_hosts verification failure with certificates
I recently upgraded one of my machines to latest Ubuntu 22.04, and now I am experiencing a very strange SSH server verification issue. Here is a short explanation of the situation.
I am using SSH ...
- 265
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1
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40
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Remotely rebooting linux mint server(SSH): permission denied (needed to enter password manually in the server)
I have a simple ssh server setup, an old Macbook air (XFCE Mint). I'm new in the topic and would like to try out some of the basic commands. tried rebooting the server by reboot from my client, ...
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2
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156
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SSH connection freezes when receiving large amount of data
I'm having issues with a series of GNU/Linux industrial devices that I connect to via SSH. The configuration is very basic, as I haven't made any changes to the server, and on the client side, I only ...
- 1,154
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54
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Examples of high MaxStartups or Max Session in use
I run a bitbucket instance where there are 4000s+ unique users per day, however sometimes users receive the error: kex_exchange_identification: Connection closed by remote host - the current config ...
- 1
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384
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How to fix fatal: Access denied for user A by PAM account configuration [preauth]?
Updated openssh to sshd 8.1. Error connecting to server: sshd fatal: Access denied for user A by PAM account configuration [preauth]
Configured ldap, authorization by key.
I don't understand what's ...
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103
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sshd log verbose filter out specific user
I would to filter out one specific user that very often connect to my servers via sshd.
I no more want to see into ssh's logs the connexion of this user.
Is it possible to do that ? to keep the actual ...
- 77
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184
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How to restart sshd after assembly?
it is necessary to update the openssh server to the latest version, since everything is closed, it has come to manually assemble it
./configure --prefix=/usr --with-pam --with-selinux --with-privsep-...
- 103
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93
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Setting up SSH Password
I've been setting up ssh access to my desktop computer.
I'm running a Debian Distro.
I've enabled password authentication in the sshd_config file, and I've tried looking for the "keyboard-...
- 85
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30
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How can I modify my sshd process on an ubuntu server to log all passwords entered on failed SSH attempts by attackers? [duplicate]
If I have an Ubuntu VM exposed to the internet and multiple randoms try to brute force login to the SSH port each day, is there a way to modify the process that logs to /var/log/auth and also log the ...
- 101
1
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1
answer
50
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Allow system user (_gogs) to use ssh
I have created a system user for gogs using mkuser for the dogs git server.
I have ssh setup but discovered that when I login it closes the connection.
Looking at the console I see this error: fatal: ...
- 21
2
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1
answer
127
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Reboot only if no ssh session are active
I'm trying to think of a solution for a problem I have.
I have a server running sftp.
I sometime need to reboot this machine for updates and other maintenance but I don't want to wait for the precise ...
- 9,445
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how to diagnose the originator of the signal 15 send to sshd
I recently met a issue that my sshd keep dead repeatly, I did the following check.
from the /var/log/message, I could see the sshd keeped restarting
Apr 23 12:05:39 host1 systemd: Stopping OpenSSH ...
- 31
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3
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Ansible: Add user in sshd_config
A new employee has joined and I need to allow him to access test servers. Normally I use template and upload this template on servers depending on the type of environment. But this time I want to use ...
- 4,178
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32
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Individual connection of people via ssh
I have different users on the server and each of them has a username and password
I want each user with his own username to be able to connect to the server with only one device at a time and not to ...
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136
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gssapi-with-mic authentication from Windows to CentOS 7.9
We are a Windows shop with some CentOS servers, which we recently joined to our domain using realmd.
I can successfully log into each CentOS using my domain username and password. Now, I'm trying to ...
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31
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When connecting to SSH externally, it shows as connected from the external source IP sometimes and other times it's from the internal gateway's IP
I have setup port forwarding rules on the firewall which maps external ports to internal SSH ports. The SSH port forwarding rules are for systems running on different OSes including CentOS 6, CentOS 7 ...
- 481
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39
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Run bash file when SSH login failure
I'm trying to execute a bash file whenever there's a failed attempted login via SSH onto my Ubuntu server.
Can anyone suggest how to do this?
As an aside, I'm currently running a script on a ...
- 101
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48
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In accessing console via serial connection, is there some "serial daemon" listening in the server?
When we use SSH, we should have an SSH client on the client computer and there should be an SSH server running on the remote computer. In Linux for example, the SSH daemon, sshd, should be running in ...
- 103
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46
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Can one configure per-client non-closing SSH session on server side?
On SSH client side one can configure per-server keepalives so that connection to a single server is kept up:
Host example
Hostname example.com
ServerAliveInterval 240
On server side one can ...
- 2,347
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0
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247
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Really strange problem with SSH disconnecting immediately, lots of investigation done
I have 3 raspberry pis with identical SD cards, for some reason one of them suddenly disconnects immediately after SSH authentication.
The problem doesn't occur immediately, reboot will fix it, and ...
- 388
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1
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279
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Ssh connection refused for existing hosts debian bullseye
There is this weird bug, where clients that have previously connected to the server via ssh, upon disconnecting and trying to reconnect at a later time, receive a "port 22 Connection refused"...
- 262
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1
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72
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SSH login still ask password even though public key is added in remote machine's ~/.ssh/authorized_keys file
I have a Raspberry pi 4 with a Linux OS & I am using a Macbook. The two machines are in the same LAN.
Raspberry pi IP address is 192.168.10.11. I can ping the Raspberry Pi from my MacBook terminal ...
- 231
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35
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Can I limit a user to only be able to upload a file to a single directory via scp?
I would like to create a ci user on a device to allow for a pipeline to drop a file into a single directory only.
I have created a user using:
useradd -M -N -r -s /bin/false devops
chown -R devops /...
- 141
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266
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/var/log/auth.log is flooded with error: connect_to 127.0.0.1 port 7300 error
I am using SSH Direct with napsternetv on my phone (iPhone and android) which sets Udpgw port 7300. This lead to flooding server /var/log/auth.log with the following error message:
[date] [time] root ...
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How to read and debug SSH verbose-mode?
Let's say I use this command:
ssh -vvv user@server
I get an output similar to this:
send packet: type 21
ssh_set_newkeys: mode 1
receive packet: type 6
SSH2_MSG_SERVICE_ACCEPT received
receive packet:...
- 540
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How to disable weak HMAC Algorithms? Not found in ssh_config or sshd_config file
A vulnerability scan showed that in a Debian 10 system, insecure MAC algorithms are in use: [email protected],[email protected],[email protected],hmac-sha1
When I do ssh -Q mac, I get ...
- 117
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2
answers
329
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SFTP issue with profile output
After SFTP logins were no longer working with error 127 we found that the SSH connection created some output by a script installed in /etc/profile.d/.
Previous versions of sshd had an option available ...
- 824
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3k
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How do I troubleshoot when systemctl will not restart the sshd service?
Long story short: I want to restart the sshd service because I think it might solve an issue I'm having using ssh on localhost. But I can't restart the sshd service; this is the problem that I am ...
- 13
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45
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Allowing public key server access only for non-interactive shells
So we have setup a login service at our big company. In short if you come from within a recognized network you only need a public key to ssh in, otherwise you need to enter a 2FA code.
Our pam.d/sshd ...
- 165
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79
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100% packet loss banana pi m2 zero, using an armbian release
I've cracked my head on this for a while. I can't ssh into my banana pi m2 zero(I don't have a mini-usb cord, I'm trying to boot wirelessly for the first time). I get 100% packet loss every time I try ...
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71
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Checking ssh connection
Is it possible to detect the activity of the ssh connection when the connection is broken.
I connect to the server via phone (ssh client) and turn off the internet, but the system (w, netstat) says I'...
2
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1
answer
727
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Is there a way to check when an ssh key from authorized_keys was last used?
My authorized_keys on some of my debian flavoured servers have become bloated with keys from old PCs, etc. Is there a way I can tell which key has been used to log in? I would like to clean it up.
I ...
- 163
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388
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Failing at SSH Agent Forwarding
I have a DigitalOcean droplet into which I'm attempting to clone a repo from Github.
This works fine on my local machine, and I've been following the guide from Github here:
https://docs.github.com/en/...
- 133
3
votes
3
answers
462
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sshd: add AllowUsers for current session, without editing sshd_config
I want to grant root access temporarily from ip 1.2.3.4, just for the current session (until next sshd or server restart)
I could add this to sshd_config, and then remember to remove it:
AllowUsers ...
