the secure shell (SSH) daemon

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-4
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1answer
76 views

How to disable ssh remote login using tcp wrapper [closed]

I want to use tcp wrapper to disable ssh remote login from a client on the server. How do I find out if sshd supports tcp wrapper and hence use it to disable ssh login?
4
votes
1answer
54 views

How to avoid calling 'startx' upon ssh login

my current situation is that in my .zprofile file I have the following line I found somewhere on the internet [[ -z $DISPLAY && $XDG_VTNR -eq 1 ]] && exec startx I think it's ...
5
votes
2answers
72 views

Isolate SSH Authentication Failures into Own Log File on RHEL 6.6

This may be impossible, but I've got a case where we want to log SSH authentication failures separately from standard SSH logging on a RHEL 6.6 box. I am aware we can use SyslogFacility with ...
0
votes
1answer
37 views

What does this mean :“sshd 5927 root 3u IPv4 66110 0t0 TCP 192.168.1.165:ssh->43.229.53.76:60 673 (ESTABLISHED)”

I tried to check who is connecting to my server and got this line I could not recognized. I used sudo lsof -i -n | egrep '\<ssh\>'. And these lines looks odd to me: sshd 5921 sshd ...
1
vote
2answers
2k views

SSH Connection Refused In CentOS?

For a week, SSH was working perfectly. Today I restarted my server and I got this error in my Mac terminal: ssh: connect to host 162.243.7.7 port 22: Connection refused This is very odd... I am ...
1
vote
0answers
98 views

Unable to ssh in to machine behind router

I'm trying to ssh into a desktop which is behind a router from a remote location. I've set the router (TP-link AC1750) to forward TCP connections to port 8000 along to port 8000 on my desktop using ...
2
votes
2answers
85 views

Does keyboard-interactive authentication support two sequential passwords?

Keyboard-interactive authentication(RFC 4256), which is implemented as ChallengeResponseAuthentication in OpenSSH configuration file, allows one to chain multiple authentication methods. For example ...
4
votes
2answers
58 views

Understand the PasswordAuthentication in sshd configuration

I have an OpenSSH server which supports only password authentication: [martin@ ~]$ ssh -v 10.10.1.183 -l root OpenSSH_5.2p1 FreeBSD-20090522, OpenSSL 0.9.8k 25 Mar 2009 debug1: Reading configuration ...
7
votes
2answers
6k views

Can't login to a remote machine with key

I used to login to a remote machine( I have to root of this machine) using key. Both my local machine and remote machine is in f23. From last few days, I can't login to this machine using key. It is ...
3
votes
2answers
443 views

SSH - Connection closed after correct login

I had SSH working on my Raspberry but suddenly it's not working anymore and I get the follwing output. Any help is really appreciated. Thanks, ssh -vvv pi@192.168.1.151 OpenSSH_6.9p1, LibreSSL 2.1....
4
votes
2answers
110 views

How to change service type of well defined ports in SElinux (centOS 6.5)

I need to be able to run SSH on port 23 instead of 22 on CentOS 6.5. SElinux won't allow that, as it has it as tcp/23 defined in policy. Any steps on how can I go about changing service type from ...
1
vote
1answer
79 views

chroot directive in sshd_config fails to exclude users

In Ubuntu, I have this SSH server configuration set up in /etc/ssh/sshd_config: Subsystem sftp internal-sftp UsePAM yes ChrootDirectory %h ForceCommand internal-sftp GatewayPorts no ...
2
votes
0answers
83 views

Why is denyhosts not banning *some* brute force root SSH login attempts?

I recently noticed in my logwatch emails from a couple of servers that although denyhosts was doing its job for some brute force root ssh login attempts others seem to be ignored and continue to ...
0
votes
0answers
22 views

Why wont my ssh key work on a different port? [duplicate]

Edit: This answer, fixed my problem. I have used ssh-copy-id to move my ssh key to my server. I have changed it so that my server is listening for ssh connections on port 50505 instead of the ...
3
votes
2answers
163 views

How do I configure sshd to 1) require public key _and_ 2) require a password for login?

How do I configure sshd to 1) require public key and 2) require a password for login? Note that I am not referring to the symmetric encryption of the client's key here. I am referring to a server-side ...
0
votes
0answers
443 views

How to restart ssh server / sshd on Linux?

I am trying to restart the ssh server on my server which is running Fedora Cloud. I have tried the method here http://www.cyberciti.biz/faq/howto-restart-ssh/ (# service sshd restart) and get Failed ...
1
vote
1answer
66 views

CentOS - SSH - File That Change Iunput Setup

I use CentOS 7 and I need to change the file that delivers the SSH configuration /etc/ssh/sshd_config to /etc/ssh/sshd_config_other. This demand was due to a security automation that always ...
2
votes
2answers
490 views

Can't connect to another user than root through SSH

I'm trying to connect to a server on my local network using SSH and would like to be able to login as storm but not as root (for obvious security purposes). I copied my .pub key to the .ssh/...
2
votes
1answer
115 views

How to Use who/w with Non-Interactive SSH logins

I'd like to perform selective shutdown of a server in my house after backing-up over SSH. My post-backup script waits for five minutes and then runs a very short 'safe shutdown' script located on the ...
2
votes
2answers
87 views

Openssh server: fatal: Too many listen sockets. Enlarge MAX_LISTEN_SOCKS [closed]

I am using Ubuntu 14.04 LTS. I want to create an openssh server, which listens on many ports (at least 100 different ports). Multiple clients would connect to this server, but each client would need ...
2
votes
1answer
36 views

Specific user's SSH-RSA with root access (via AWS EC2)

Is it possible to set up a specific SSH-RSA key (via another user i.e. "ec2-user") to have ability to sudo into root. I.e. You login with key to "Bob" (ec2-user). Currently user "Bob" can sudo ...
2
votes
3answers
446 views

Allow SSH access but restrict root's access to a given set of IPs

I want to allow SSH for all users as normal except that I want to restrict root's access based on a set of IP addresses. So, users peter, paul, lary can login from anywhere, but root may login only ...
1
vote
2answers
68 views

Cannot login over ssh

I did something very stupid. I created user accounts on my linux server, then I disabled password logins. I configured ssh to not accept password logins and only accept ssh. I configured the ufw ...
1
vote
1answer
79 views

iptables and ssh

I'm running Arch Linux and I have a running SSH daemon to access my machine when I'm out side my LAN. I can do the connection, but iptables keeps blocking SSH Daemon, so I can only connect if I turn ...
0
votes
1answer
43 views

opensshd / openssh - allow EITHER keypair or password

I would like to configure my sshd to allow users to authenticate with a keypair, then fallback to password authentication. But I'm struggling to achieve that from the information in the man pages / ...
0
votes
1answer
53 views

Error becoming root centos

I'm getting the following error when I'm trying to become root -bash-4.1$ sudo su - Could not open a connection to your authentication agent. * Error: Problem adding; giving up I have tried eval "$(...
1
vote
2answers
113 views

Unexpected Match behavior in sshd_config

I'm trying to configure the following restrictions in my sshd_config: Users with local IP addresses face no restrictions Users with non-local IP addresses, who are in the sftp group, are allowed to ...
1
vote
1answer
45 views

Is 2s a “normal” variation in ssh's execution time?

In my program, ssh "normally" takes around 0.3s, however sometimes it may take more than 2s. I wonder whether this is a normal variation for ssh's execution time, and whether there is some thing I ...
3
votes
2answers
34 views

Can resource over-utilization actually cause users to be unable to SSH to Linux?

The night support guys where I work have a tendency to reboot machines citing the fact that they can't ssh in and figure out what's going on in the first place. It's pretty much against company ...
1
vote
0answers
135 views

Reverse AutoSSH working, but the proxied LISTEN ports fail randomly

I'm having a hard time describing the error, sorry for the lengthy explanation: I have a successful, working, stable reverse AutoSSH solution nailed up between a client beagle board and a server. The ...
2
votes
0answers
413 views

“Too many open files ssh” when the number of open files is far below ulimit

I was trying to set up 2000 concurrent ssh connections, but got the error message in server log (i.e. journalctl): sshd[1356]: error: reexec socketpair: Too many open files I've set both the soft ...
7
votes
1answer
371 views

Enable Massive Concurrent SSH to a single server

My goal is to allow 10000 concurrent sshs running on a single server. For simplicity I am ssh-ing to localhost: for i in `seq 1 10000`; do ssh localhost "echo ${i}; sleep 100" >>./info 2&...
2
votes
2answers
42 views

Is there a way to tell how a user authenticated their SSH connection ? i.e. whether it was by password or by public key?

I'm locking down my server to use public-key only. I just want to make sure before I flip the switch that all my users have already made the transition, and nobody is left using passwords to log in.
2
votes
1answer
36 views

Display full settings of sshd

The OpenSSH daemon has many "default" values for its settings. So looking at the sshd_config might not give someone the complete set of active settings. How to display the full sshd configuration (...
8
votes
1answer
457 views

Blocking SSH Brute Force attacks on IPv6

I recently had to work with some servers that have an IPv6 connection and I was surprised to find out that fail2ban does not have IPv6 support, neither does denyhosts. Searching on google I found that ...
0
votes
1answer
149 views

Configure ssh users under a group [closed]

I created a group called ssh_group and currently have nearly 20 users under AllowUsers in /etc/ssh/sshd_config. After I created the ssh_group, I modified the AllowGroups line like this AllowGroups ...
0
votes
1answer
123 views

Adding user override to sshd_config causes ssh_exchange_identification error

I wanted to allow SSH TCP forwarding for a specific user, so I added this section to sshd_config: Match User rainmannoodles AllowTcpForwarding yes TCPKeepAlive yes After that change, I get ...
0
votes
0answers
85 views

SMTP traffic being forwarded through SSH even do AllowTcpForwarding is disabled

I have a situation on one server, where it seems to be spaming over traffic being sent over SSH tunnel. Output below shows connections being made to remote SMTP server that seem to be initiated over ...
2
votes
1answer
37 views

Use two SSH ports, but open only one?

My iptables.conf looks roughly like this: -A INPUT -p tcp --dport 65000 -j ACCEPT -A INPUT -j DROP My sshd_config looks like this: Port 22 Port 65000 #AddressFamily any #ListenAddress 0.0.0.0 #...
2
votes
0answers
149 views

Two ISP and redirecting traffic

I have a gateway with two ISP connected to eth0 and eth2. There is also a eth1 with local network. I'm trying to group some services in one interface and some in the second: incoming traffic 1 ...
4
votes
3answers
5k 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 ...
0
votes
0answers
339 views

xterm Xt error: Can't open display: localhost:11.0

I'm on a windows machine running Xming32, putty and plink. I have two centos boxes. One I can connect to just fine. The other I can't. I'm trying with this command plink -C -v jdearing@BROKENHOST ...
4
votes
1answer
222 views

sudo command inside heredoc block in a ssh session is not working

When i use heredoc and put all the commands inside heredoc as, ssh -t -i master.pem cloud-user@$1 <<EOSSH sudo service x restart sudo service y restart EOSSH it throws error as, Pseudo-...
1
vote
1answer
335 views

How to ensure ssh via cgroups on centos?

When some cpu-intensive processes are running on the server, chances are that we could not log in to this machine with error 'operation timeout' via ssh command. According to this post answered by ...
1
vote
1answer
5k 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 /etc/...
2
votes
1answer
57 views

Is sshd_config TPCKeepAlive still using unencrypted channel and therefore vulnerable

This post from 2008 in ubuntuforums recommends disabling TCPKeepAlive Disable TCP KeepAlive messages. These messages are spoofable and are sent outside of the encrypted channel, and ...
5
votes
1answer
3k views

Uselogin in sshd_config

I was looking through my sshd_config file and I found this: #Uselogin no I know it's commented but there is no explanation above it and when I google it, I get this: Don't use the traditional ...
4
votes
5answers
295 views

Multiline Text Processing : Editing sshd_config

I have multiple blocks at the end of my sshd_config files like theses: Match User FOO ChrootDirectory /srv/www/FOO AllowTCPForwarding no X11Forwarding no ForceCommand internal-sftp ...
1
vote
2answers
500 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 ....
5
votes
3answers
9k 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 ...