Questions about the OpenSSH implementation of the ssh protocol.

learn more… | top users | synonyms

1
vote
3answers
147 views

Can't ssh to a machine

All of a sudden, I couldn't ssh to a machine to which I used to ssh earlier. Consider I am ssh-ing from A to B. Output when I run ssh root@ip_addr_of_B I get: Permission denied ...
3
votes
1answer
133 views

How to know which public key was used when someone used passwordless ssh login?

Say for some reason, there is only a "user" account on a shhd server. Everyone has his own private key to ssh to the server, as "user". Then, is there a way to see who is he (during or after his ...
0
votes
0answers
55 views

Problem with OpenSSH

I think I got an OpenSSH-problem with my Ubuntu Server 14.04.1. Let me explain my setup: For development, I use Git and Gitolite. I have 3 server: server A ( master-server for git-mirroring) ...
4
votes
0answers
235 views

Can't figure out why ssh_exchange_identification: Connection closed by remote host appear

At home, I have setup a Raspberry Pi with the latest version of Raspbian and with ssh enabled. I also use a Mac Book Pro with OS X 10.9.3. I use ssh pi@192.168.0.22 to do some work on the Raspberry ...
0
votes
1answer
113 views

What is the default idle timeout for OpenSSH?

I can't seem to find an answer to this simple question, which I need for some compliance documentation. On a default install of CentOS 6.5 (OpenSSH 5.3p1-94.el6), after how long of being idle will ...
2
votes
1answer
42 views

Only apply Match keyword to single Host in ssh config

I have a host which I ssh into. Sometimes I'm inside the same network, and can ssh directly into it, other times I'm outside it and I need to use a proxy. Because ssh via the proxy server is much ...
2
votes
1answer
109 views

SSH: public key authentication without authorized_keys file

I have a lot of ssh public key logins on a Linux server, e.g.: Jul 25 11:41:01 host sshd[24594]: Accepted publickey for root from xxx.xxx.xx.xx port 33374 ssh2 This is strange for me since there's ...
19
votes
4answers
18k views

What is the point of sshd “UseDNS” option?

I know what it does, but i don't know why. What attack(s) does it prevent ? Is it relevant for all kind of authentication methods ? (hostbased, password, publickey, keyboard-interactive ...)
16
votes
2answers
283 views

What's the purpose of the randomart image for user (not host) SSH keys?

The ssh-keygen generates the following output: The key fingerprint is: dd:e7:25:b3:e2:5b:d9:f0:25:28:9d:50:a2:c9:44:97 user@machine The key's randomart image is: +--[ RSA 2048]----+ | .o o.. ...
8
votes
3answers
526 views

Local, timestamped logging of all ssh commands?

How can I keep a local, timestamped record of all remote commands I use in ssh (command-line openssh client started through bash)? Requirements: Essential: 100% client-side without relying on ...
3
votes
2answers
87 views

Starting SSH server after VPN starts

I am running an OpenVPN server on Ubuntu 14.04 as well as OpenSSH. I have my SSH server configured to bind to an IP address on my VPN interface. Once my machine boots, binding to that IP fails. ...
1
vote
1answer
974 views

ssh_exchange_identification: Connection closed by remote host on vnx machine (linux)

I changed the password of my linux machine . I was able to login for sometime and after that I am not able to ssh. I am getting the following error: ssh es4042cs -v OpenSSH_5.1p1, OpenSSL ...
3
votes
1answer
48 views

openSuse, new user cannot login

I am using openSuse 12.3. I have created a new user using: linux-amvn:~ # useradd -m -G users,dev -s /bin/bash -p pass123 harbir-PC The user harbir-PC is not able to login, when I try to log using ...
13
votes
3answers
13k views

How do I convert a ssh-keygen public key into a format that openssl PEM_read_bio_RSA_PUBKEY() function will consume?

I'm having an issue generating a public key that the openssl PEM_read_bio_RSA_PUBKEY() function can consume. I keep getting errors. Obviously I cannot simply use the ASCII string in the ssh-keygen ...
1
vote
0answers
30 views

How to get information from sshd about established remote tunnels

I have a server running on which from many different places people log on via ssh and open remote ssh-tunnels to other places behind different firewalls. Now I want to try to get an overview, which ...
1
vote
0answers
14 views

Why does wget return a HTTP 403 error to download openSSH pet? [duplicate]

I am trying to learn how I would get OpenSSH using the command line. I found a *.pet link on this webpage: http://puppylinux.org/wikka/OpenSSH which says: Installation Install an appropriate ...
2
votes
1answer
66 views

how to connect ssh 'with' specified port?

I know how to connect 'to' a certain port when ssh'ing. ssh user@remotehostip -p XXX but is there a way to establish a ssh 'with' a certain port? I mean, is there a way to specify the port which ...
4
votes
1answer
62 views

How to exclude from a “Match Group” in SSHD?

There is a Match group in the SSHD config: cat /etc/ssh/sshd_config ... Match Group FOOGROUP ForceCommand /bin/customshell ... There are many users on the machine that are in the ...
1
vote
1answer
123 views

Help updating OpenSSH to v6.6

My system is vulnerable to OpenSSH Wildcards on AcceptEnv Vulnerability, CVE-2014-2532. I have tried to update openssh to version 6.6 for centos but I can not get repository[sic] for that version. ...
1
vote
1answer
77 views

Compiling OpenSSH client or Dropbear for Android

I have an interesting problem. I'd like to use a private SSH key with my Android Terminal Emulator (jackpal.androidterm). I'd like to install the private key in a fairly-secure location and be able ...
2
votes
1answer
140 views

Are dropbear and OpenSSH host keys compatible?

The title basically says it all. But mind: host key, not the login key. And if they're not compatible out of the box, is there a way to convert between them - and what would be the steps in that ...
0
votes
0answers
36 views

Proxy from OSX laptop to debian server for web browsing

I want to setup a proxy from my OSX laptop (10.9) to a debian server via SSH, to browse the net via that server. The debian server has an openssh-server running, and I can login. I tried several ...
6
votes
3answers
308 views

How to prevent “Last Login:” message from showing up when using sftp?

In Ubuntu GNU/Linux 12.04, I have a user johndoe that is part of an sftponly group, set up to sftp to a chroot jail using Subsystem sftp internal-sftp Match Group sftponly ChrootDirectory %h ...
2
votes
1answer
63 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 ...
2
votes
2answers
522 views

check if latest openssh patch provided by RHEL is installed

We have encountered a security threat in one of our RHEL servers which says the SSH server is configured to use Cipher Block Chaining. As far as I know, the RHEL systems provide security updates ...
6
votes
1answer
159 views

Determine dynamically allocated port for OpenSSH RemoteForward

Question (TL;DR) When assigning ports dynamically for remote forwarding (a.k.a. -R option), how can a script on the remote machine (for instance sourced from .bashrc) determine which ports were ...
2
votes
1answer
250 views

Generate own (stronger) RSA host key for OpenSSH?

I would like to replace the default 2048 bit host key generated when installing OpenSSH or starting it the first time with one of 4096 bit length. This leads to two questions: Does OpenSSH allow ...
3
votes
2answers
86 views

using ssh-agent

I have my desktop in the office. When X starts, ssh-agent starts automatically. I have to add my SSH key once, at the beginning, and then I can use ssh without having to enter my password each time. ...
0
votes
3answers
275 views

How I Determine The latest OpenSSL patch is installed?

This post is about applying the latest patch for OpenSSL to protect our port 443 web traffic, not using ssh to log into these systems. I went and obtained the lastest OpenSSL tarball source patch ...
1
vote
0answers
444 views

Force ssh to always use SSH_ASKPASS

I want to force ssh to always use the program specified by SSH_ASKPASS. In my case the program is just a bash script returning the passphrase. The problem is, as the ssh documentation says: If ...
1
vote
0answers
167 views

SSH to Windows 7 with cygwin openSSH freezes when remote conection [closed]

When I SSH into Windows 7(Cygwin) from a remote, the session freezes after few seconds or up to two minutes. This can happen while I'm typing and it can happen when idle. This is still happening after ...
3
votes
1answer
48 views

Accept any private key for authentication

Is it possible to configure OpenSSH (or any other standard sshd) to accept any key offered by a connecting client? EG ssh -i ~/arbitraryKey hostname grants a login shell while ssh hostanme doesn't. ...
3
votes
2answers
132 views

Denying “/opt/” access for SFTP Users other than particular dir

This is my first (newbie) post here in unix stackexchange. I want to use my WebServer (Debian) as SFTPServer giving access to particular employees. The dir structure is as follows under root: ...
0
votes
1answer
182 views

Understand debug messages from sshd [closed]

I'm using OpenSSH_5.8p1 in my machine,I'm connecting my machine using putty client but its slower so I have ran sshd in debug mode and found following messages can any one explain me in detail about ...
0
votes
0answers
91 views

sshd without pam slower

I am running OpenSSH_6.5 with UsePAM yes in my board. I have observed that with UsePAM no in /etc/ssh/sshd_config, sshd runs slower than previous case. How is this possible? My understanding is ...
1
vote
3answers
4k 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 ...
1
vote
1answer
172 views

ssh connection fails after login at one user

Have server with 2 users - (e.g. - user and root). SSH login to root works corrctly. But I can't login to user - it immediatelly fails with "write failed - broken pipe" after login. ssh -vvv ...
1
vote
1answer
569 views

How can I have a SSH banner appear BEFORE the “login as:” prompt? [duplicate]

CentOS 5.x When I enable the Banner /path/to/banner parameter in my sshd config file, the banner displays AFTER the login as: prompt. For example: login as: foo ...
2
votes
1answer
1k views

Single command to login to SSH and run program?

Is there a way to structure a single command to login via SSH to a remote server and run a program on the remote login shell? In the OpenSSH manual, it reads "If command is specified, it is executed ...
11
votes
4answers
5k views

Given keys in ~/.ssh/authorized_keys format, can you determine key strength easily?

~/.ssh/authorized_keys[2] contains the list of public keys. Unfortunately, each public key does not specify the key strength ( number of bits ). Is there a utility that can process this file line by ...
1
vote
0answers
100 views

git push in gnome-term crashes my window manager

In terminal in awesome wm when i git push awesome wm freezes. so i move over to tty2 and log in. top shows awesome at %100 cpu. ps aux | grep [g]it output git-remote-https origin ...
0
votes
1answer
168 views

SSH to Linux Container from Other Machine

I am trying to learn about Linux Containers and this is my first encounter with servers, ssh and many other things that I do not know the terms yet. I create five different containers and authorized ...
2
votes
2answers
351 views

SSH access from inside and outside a LAN using the same terminal command

I have a Raspberry Pi (RPi) and I am making remote connections to it using ssh. I have managed to set up ssh correctly such that I can access the RPi both from a local area network and from the ...
-1
votes
1answer
129 views

Double port forwarding - SSH

NOTE: I'm not explaining why I want to do this. But here is the requirement. There are 4 hosts. Host A, Host B, Host C, Host D Host A is running some application which can be accessed at port 8001 ...
0
votes
0answers
612 views

OpenSSH hangs after login without showing login prompt

I ran across an issue with ssh after fresh Ubuntu 13.10 installation on Lenovo T420. I tried git pull (which failed) and this led me to more general ssh failing. After spending some 2-3 hrs of ...
0
votes
1answer
75 views

Linux Fedora Core 18 freezes on OpenSSH login

miagos:~ $ uname -a Linux miagos 3.9.6-200.fc18.x86_64 #1 SMP Thu Jun 13 18:56:55 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux I have a reproducible issue, when my desktop Linux node stays online for more ...
4
votes
2answers
102 views

Why are rules not combining in an ssh config file?

It seems like the following would work as expected, i.e., that the second rule, having a hostname that matches the first rule, would apply it. Host *.hostname.com User myuser IdentityFile ...
1
vote
1answer
213 views

Setting the bash SHELL for remote openSSH connections?

I am connected to a Freebsd 10 -STABLE server with SSH from my office box but when I trying to work inside the session I encounter these problems: although I did chsh for every user in said server ...
4
votes
2answers
136 views

SSH - How to make X applications run on client?

I have the reverse problem that most people seem to be having. If I start an X application while logged into ssh, it displays on the server(host) machine instead of the client(local). This is the ...
0
votes
1answer
42 views

Supply additional ssh options in config file

How can I supply additional options in .ssh/config? I know that information like Host, Port, User etc. may be used in the ssh-configuration file to abbreviate ssh commands. I frequently create ...