Ssh (Secure Shell) FAQ - Frequently asked questions
by
Thomas König
Thomas.Koenig@ciw.uni-karlsruhe.de
$Date: 1997/06/06 20:14:08 $
This document is a list of Frequently Asked Questions (plus hopefully correct answers) about the Secure Shell, ssh.
1.
Meta-questions
1.1 Where do I get this document?
1.2 Where do I send questions, corrections etc. about this document?
2.
Ssh basics
2.1 What is ssh?
2.2 Why should I use it?
2.3 What kinds of attacks does ssh protect against?
2.4 What kind of attacks does ssh not protect against?
2.5 How does it work?
3.
Obtaining and installing ssh
3.1 What is the latest version of ssh?
3.2 May I legally run ssh?
3.3 What about commercial use of ssh?
3.4 Where can I obtain ssh?
3.5 How do I install it?
3.6 Does it make sense to install ssh as non-root under UNIX?
3.7 Where do I get help?
3.8 Are there any versions for other operating systems than UNIX?
3.9 What about administration of ssh?
4.
Ssh Applications
4.1 Can I run backups over ssh?
4.2 Should I turn encryption off, for performance reasons?
4.3 Can I use ssh to communicate across a firewall?
4.4 Can I use rdist with ssh?
4.5 Can I use ssh to securely connect two subnets across the Internet?
4.6 Can I use ssh to securely forward UDP-based services, such as NFS or NIS?
4.7 Can I forward SGI GL connections over ssh?
4.8 Can I use ssh to protect services like ftp or POP?
4.9 Can I use ssh across a Socks firewall?
4.10 Is there ssh support for AFS/Kerberos?
5.
Problems
5.1 ssh otherhost xclient & does not work!
5.2 Ssh fails with "Resource temporarily unavailable" for Solaris
5.3 Sshd hangs under Solaris 2.5!
5.4 X11 forwarding does not work for an SCO binary with the iBCS2 emulator under Linux.
5.5 Ssh is doing wrong things for multi-homed hosts!
5.6 Userid swapping is broken under AIX!
5.7 ssh-keygen dumps core on Alpha OSF!
5.8 ssh-keygen dumps core on Solaris or SunOS
5.9 On Linux, compilation aborts with some error message about libc.so.4
5.10 X authorization sometimes fails.
5.11 Ssh asks me for passwords despite .rhosts!
5.12 Why does ssh loop with "Secure connection refused'?
5.13 ssh-agent does not work with rxvt!
5.14 X authorization always fails.
5.15 ssh hangs when forwarding multiple TCP connections.
5.16 What does Warning: remote host denied X11 forwarding mean?
5.17 I still see cleartext packages on the net when I run ssh!
5.18 I have problems with RSAREF, something to do with too many bits!
5.19 Compiling fails with some error messages from the assembler.
5.20 Compiling with Solaris 2.5 fails!
5.21 Ssh suddenly drops connections!
5.22 Connections are forwarded as root by ssh!
6.
Miscellaneous
6.1 What known security bugs exist in which versions of ssh?
6.2 How widespread is use of ssh?
6.3 I don't like the commercial aspects of ssh.
6.4 Credits