tramp (2.0.36); SSH Host key verification failed (on ssh forwarded port from remote to localhost)

[Ferruccio Zamuner]

Enter your bug report in this message, including as much detail as you
possibly can about the problem, what you did to cause it and what the
local and remote machines are.

If you can give a simple set of instructions to make this bug happen
reliably, please include those.  Thank you for helping kill bugs in
TRAMP.

Another useful thing to do is to put (setq tramp-debug-buffer t) in
the ~/.emacs file and to repeat the bug.  Then, include the contents
of the *tramp/foo* buffer and the *debug tramp/foo* buffer in your bug
report.

--bug report follows this line--
Hi tramp-devel,

I've to access to remote host using a ssh-proxy; usually I forward
the remote host ssh port to localhost using the ssh tunneling:

ssh -c blowfish -L2001:remotehost:22 address@hidden

then the proxy ask me for password, remotehost's account
then the remotehost's address

After this first phase I can easly access to the remotehost using

ssh -X -p 2001 address@hidden


And I can enter and do everything on the remote system.

Anyway the GnuEmacs is slow if used in such X11 forwarded environment.


Today I've first try to use ange-ftp forwarding the ftp port too,
but I'd not success.

Then I've found some info about tramp, then I've read the documentation
and I've started to try:

/ssh:address@hidden:/path/file


But I've got the error on:
-----------------------------------------
...
Offending key in /home/fer/.ssh/known_hosts:1
DSA host key for localhost has changed and you have requested strict checking.
Host key verification failed.
...
-----------------------------------------

So I've gone on address@hidden where I've looked for help,
but I've been able to fix the problem.


I've tried also the multi: without success.


I've seen trampmode to work from my installation on another host
where I don't need to login via the ssh gateway.


I hope to have give you usefull information to understand the problem
and to make next release a bit better.


Best wishes,             \fer
---------------------------------------------------------------------

Emacs  : GNU Emacs 21.3.1 (i386--freebsd, X toolkit, Xaw3d scroll bars)
 of 2004-02-10 on k7.diff.org
Package: tramp (2.0.36)

current state:
==============
(setq
 tramp-ls-command nil
 tramp-test-groks-nt nil
 tramp-file-exists-command nil
 tramp-current-multi-method nil
 tramp-current-method "ssh2"
 tramp-current-user "fer"
 tramp-current-host "localhost"
 tramp-auto-save-directory nil
 tramp-default-method "ssh2"
 tramp-rsh-end-of-line "\n"
 tramp-default-password-end-of-line "\n"
 tramp-remote-path '("/bin" "/usr/bin" "/usr/sbin" "/usr/local/bin"
                     "/usr/ccs/bin" "/local/bin" "/local/freeware/bin"
                     "/local/gnu/bin" "/usr/freeware/bin" "/usr/pkg/bin"
                     "/usr/contrib/bin")
 tramp-login-prompt-regexp ".*ogin: *"
 tramp-password-prompt-regexp "^.*\\([pP]assword\\|passphrase.*\\):
 tramp-wrong-passwd-regexp "^.*\\(Connection 
\\(?:\\(?:clo\\|refu\\)sed\\)\\|Host key verification failed\\.\\|Login 
\\(?:[Ii]ncorrect\\)\\|Name or service not known\\|\\(?:Permission 
denied\\|Sorry, try again\\)\\.\\).*\\|^.*\\(Received signal [0-9]+\\).*"
 tramp-yesno-prompt-regexp "\\(Are you sure you want to continue connecting 
(yes/no)\\?\\)\\s-*"
 tramp-yn-prompt-regexp "\\(Store key in cache\\? (y/n)\\)\\s-*"
 tramp-temp-name-prefix "tramp."
 tramp-file-name-structure '("^/\\(\\([a-zA-Z_0-9-]+\\):\\)?\\(\\([^:@/         
]*\\)@\\)?\\([a-zA-Z0-9_.#-]*\\):\\(.*$\\)" 2 4 5 6)
 tramp-file-name-regexp "\\`/[^/:]+:"
 tramp-multi-file-name-structure 
'("^/\\(\\([a-zA-Z_0-9-]+\\)\\)?\\(\\(:%s\\)+\\)?:\\(.*$\\)" 2 3 -1)
 tramp-multi-file-name-hop-structure '("\\([a-zA-Z_0-9-]+\\):\\([^:@/   
]*\\)@\\([a-zA-Z0-9_.#-]*\\)" 1 2 3)
 tramp-multi-methods '("multi" "multiu")
 tramp-multi-connection-function-alist '(("telnet" tramp-multi-connect-telnet
                                          "telnet %h%n")
                                         ("rsh" tramp-multi-connect-rlogin
                                          "rsh %h -l %u%n")
                                         ("remsh" tramp-multi-connect-rlogin
                                          "remsh %h -l %u%n")
                                         ("ssh" tramp-multi-connect-rlogin
                                          "ssh %h -l %u%n")
                                         ("su" tramp-multi-connect-su
                                          "su - %u%n")
                                         ("sudo" tramp-multi-connect-su
                                          "sudo -u %u -s -p Password:%n")
                                         )
 tramp-methods '(("smb") ("ftp")
                 ("rcp" (tramp-connection-function tramp-open-connection-rsh)
                  (tramp-login-program "rsh") (tramp-copy-program "rcp")
                  (tramp-remote-sh "/bin/sh") (tramp-login-args nil)
                  (tramp-copy-args nil) (tramp-copy-keep-date-arg "-p")
                  (tramp-password-end-of-line nil))
                 ("scp" (tramp-connection-function tramp-open-connection-rsh)
                  (tramp-login-program "ssh") (tramp-copy-program "scp")
                  (tramp-remote-sh "/bin/sh") (tramp-login-args ("-e" "none"))
                  (tramp-copy-args nil) (tramp-copy-keep-date-arg "-p")
                  (tramp-password-end-of-line nil))
                 ("scp1" (tramp-connection-function tramp-open-connection-rsh)
                  (tramp-login-program "ssh") (tramp-copy-program "scp")
                  (tramp-remote-sh "/bin/sh")
                  (tramp-login-args ("-1" "-e" "none"))
                  (tramp-copy-args ("-1")) (tramp-copy-keep-date-arg "-p")
                  (tramp-password-end-of-line nil))
                 ("scp2" (tramp-connection-function tramp-open-connection-rsh)
                  (tramp-login-program "ssh") (tramp-copy-program "scp")
                  (tramp-remote-sh "/bin/sh")
                  (tramp-login-args ("-2" "-e" "none"))
                  (tramp-copy-args ("-2")) (tramp-copy-keep-date-arg "-p")
                  (tramp-password-end-of-line nil))
                 ("scp1_old"
                  (tramp-connection-function tramp-open-connection-rsh)
                  (tramp-login-program "ssh1") (tramp-copy-program "scp1")
                  (tramp-remote-sh "/bin/sh") (tramp-login-args ("-e" "none"))
                  (tramp-copy-args nil) (tramp-copy-keep-date-arg "-p")
                  (tramp-password-end-of-line nil))
                 ("scp2_old"
                  (tramp-connection-function tramp-open-connection-rsh)
                  (tramp-login-program "ssh2") (tramp-copy-program "scp2")
                  (tramp-remote-sh "/bin/sh") (tramp-login-args ("-e" "none"))
                  (tramp-copy-args nil) (tramp-copy-keep-date-arg "-p")
                  (tramp-password-end-of-line nil))
                 ("rsync"
                  (tramp-connection-function tramp-open-connection-rsh)
                  (tramp-login-program "ssh") (tramp-copy-program "rsync")
                  (tramp-remote-sh "/bin/sh") (tramp-login-args ("-e" "none"))
                  (tramp-copy-args ("-e" "ssh"))
                  (tramp-copy-keep-date-arg "-t")
                  (tramp-password-end-of-line nil))
                 ("remcp"
                  (tramp-connection-function tramp-open-connection-rsh)
                  (tramp-login-program "remsh") (tramp-copy-program "rcp")
                  (tramp-remote-sh "/bin/sh") (tramp-login-args nil)
                  (tramp-copy-args nil) (tramp-copy-keep-date-arg "-p")
                  (tramp-password-end-of-line nil))
                 ("rsh" (tramp-connection-function tramp-open-connection-rsh)
                  (tramp-login-program "rsh") (tramp-copy-program nil)
                  (tramp-remote-sh "/bin/sh") (tramp-login-args nil)
                  (tramp-copy-args nil) (tramp-copy-keep-date-arg nil)
                  (tramp-password-end-of-line nil))
                 ("ssh" (tramp-connection-function tramp-open-connection-rsh)
                  (tramp-login-program "ssh") (tramp-copy-program nil)
                  (tramp-remote-sh "/bin/sh") (tramp-login-args ("-e" "none"))
                  (tramp-copy-args nil) (tramp-copy-keep-date-arg nil)
                  (tramp-password-end-of-line nil))
                 ("ssh1" (tramp-connection-function tramp-open-connection-rsh)
                  (tramp-login-program "ssh") (tramp-copy-program nil)
                  (tramp-remote-sh "/bin/sh")
                  (tramp-login-args ("-1" "-e" "none"))
                  (tramp-copy-args ("-1")) (tramp-copy-keep-date-arg nil)
                  (tramp-password-end-of-line nil))
                 ("ssh2" (tramp-connection-function tramp-open-connection-rsh)
                  (tramp-login-program "ssh") (tramp-copy-program nil)
                  (tramp-remote-sh "/bin/sh")
                  (tramp-login-args ("-2" "-e" "none"))
                  (tramp-copy-args ("-2")) (tramp-copy-keep-date-arg nil)
                  (tramp-password-end-of-line nil))
                 ("ssh1_old"
                  (tramp-connection-function tramp-open-connection-rsh)
                  (tramp-login-program "ssh1") (tramp-copy-program nil)
                  (tramp-remote-sh "/bin/sh") (tramp-login-args ("-e" "none"))
                  (tramp-copy-args nil) (tramp-copy-keep-date-arg nil)
                  (tramp-password-end-of-line nil))
                 ("ssh2_old"
                  (tramp-connection-function tramp-open-connection-rsh)
                  (tramp-login-program "ssh2") (tramp-copy-program nil)
                  (tramp-remote-sh "/bin/sh") (tramp-login-args ("-e" "none"))
                  (tramp-copy-args nil) (tramp-copy-keep-date-arg nil)
                  (tramp-password-end-of-line nil))
                 ("remsh"
                  (tramp-connection-function tramp-open-connection-rsh)
                  (tramp-login-program "remsh") (tramp-copy-program nil)
                  (tramp-remote-sh "/bin/sh") (tramp-login-args nil)
                  (tramp-copy-args nil) (tramp-copy-keep-date-arg nil)
                  (tramp-password-end-of-line nil))
                 ("telnet"
                  (tramp-connection-function tramp-open-connection-telnet)
                  (tramp-login-program "telnet") (tramp-copy-program nil)
                  (tramp-remote-sh "/bin/sh") (tramp-login-args nil)
                  (tramp-copy-args nil) (tramp-copy-keep-date-arg nil)
                  (tramp-password-end-of-line nil))
                 ("su" (tramp-connection-function tramp-open-connection-su)
                  (tramp-login-program "su") (tramp-copy-program nil)
                  (tramp-remote-sh "/bin/sh") (tramp-login-args ("-" "%u"))
                  (tramp-copy-args nil) (tramp-copy-keep-date-arg nil)
                  (tramp-password-end-of-line nil))
                 ("sudo" (tramp-connection-function tramp-open-connection-su)
                  (tramp-login-program "sudo") (tramp-copy-program nil)
                  (tramp-remote-sh "/bin/sh")
                  (tramp-login-args ("-u" "%u" "-s" "-p" "Password:"))
                  (tramp-copy-args nil) (tramp-copy-keep-date-arg nil)
                  (tramp-password-end-of-line nil))
                 ("multi"
                  (tramp-connection-function tramp-open-connection-multi)
                  (tramp-login-program nil) (tramp-copy-program nil)
                  (tramp-remote-sh "/bin/sh") (tramp-login-args nil)
                  (tramp-copy-args nil) (tramp-copy-keep-date-arg nil)
                  (tramp-password-end-of-line nil))
                 ("scpx" (tramp-connection-function tramp-open-connection-rsh)
                  (tramp-login-program "ssh") (tramp-copy-program "scp")
                  (tramp-remote-sh "/bin/sh")
                  (tramp-login-args ("-e" "none" "-t" "-t" "/bin/sh"))
                  (tramp-copy-args nil) (tramp-copy-keep-date-arg "-p")
                  (tramp-password-end-of-line nil))
                 ("sshx" (tramp-connection-function tramp-open-connection-rsh)
                  (tramp-login-program "ssh") (tramp-copy-program nil)
                  (tramp-remote-sh "/bin/sh")
                  (tramp-login-args ("-e" "none" "-t" "-t" "/bin/sh"))
                  (tramp-copy-args nil) (tramp-copy-keep-date-arg nil)
                  (tramp-password-end-of-line nil))
                 ("krlogin"
                  (tramp-connection-function tramp-open-connection-rsh)
                  (tramp-login-program "krlogin") (tramp-copy-program nil)
                  (tramp-remote-sh "/bin/sh") (tramp-login-args ("-x"))
                  (tramp-copy-args nil) (tramp-copy-keep-date-arg nil)
                  (tramp-password-end-of-line nil))
                 ("plink"
                  (tramp-connection-function tramp-open-connection-rsh)
                  (tramp-login-program "plink") (tramp-copy-program nil)
                  (tramp-remote-sh "/bin/sh") (tramp-login-args ("-ssh"))
                  (tramp-copy-args nil) (tramp-copy-keep-date-arg nil)
                  (tramp-password-end-of-line "xy"))
                 ("plink1"
                  (tramp-connection-function tramp-open-connection-rsh)
                  (tramp-login-program "plink") (tramp-copy-program nil)
                  (tramp-remote-sh "/bin/sh") (tramp-login-args ("-1" "-ssh"))
                  (tramp-copy-args nil) (tramp-copy-keep-date-arg nil)
                  (tramp-password-end-of-line "xy"))
                 ("pscp" (tramp-connection-function tramp-open-connection-rsh)
                  (tramp-login-program "plink") (tramp-copy-program "pscp")
                  (tramp-remote-sh "/bin/sh") (tramp-login-args ("-ssh"))
                  (tramp-copy-args nil) (tramp-copy-keep-date-arg "-p")
                  (tramp-password-end-of-line "xy"))
                 ("fcp" (tramp-connection-function tramp-open-connection-rsh)
                  (tramp-login-program "fsh") (tramp-copy-program "fcp")
                  (tramp-remote-sh "/bin/sh -i")
                  (tramp-login-args ("sh" "-i")) (tramp-copy-args nil)
                  (tramp-copy-keep-date-arg "-p")
                  (tramp-password-end-of-line nil))
                 )
 tramp-end-of-output "///f578ffa3bde05fc18ee7f0961a5aa593"
 tramp-coding-commands '(("mimencode -b" "mimencode -u -b"
                          base64-encode-region base64-decode-region)
                         ("mmencode -b" "mmencode -u -b" base64-encode-region
                          base64-decode-region)
                         ("recode data..base64" "recode base64..data"
                          base64-encode-region base64-decode-region)
                         ("uuencode xxx" "uudecode -o -" tramp-uuencode-region
                          uudecode-decode-region)
                         ("uuencode xxx" "uudecode -p" tramp-uuencode-region
                          uudecode-decode-region)
                         ("uuencode xxx" "tramp_uudecode"
                          tramp-uuencode-region uudecode-decode-region)
                         ("tramp_encode_with_module"
                          "tramp_decode_with_module" base64-encode-region
                          base64-decode-region)
                         ("tramp_encode" "tramp_decode" base64-encode-region
                          base64-decode-region)
                         )
 tramp-actions-before-shell '((tramp-password-prompt-regexp
                               tramp-action-password)
                              (tramp-login-prompt-regexp tramp-action-login)
                              (shell-prompt-pattern tramp-action-succeed)
                              (tramp-shell-prompt-pattern tramp-action-succeed)
                              (tramp-wrong-passwd-regexp
                               tramp-action-permission-denied)
                              (tramp-yesno-prompt-regexp tramp-action-yesno)
                              (tramp-yn-prompt-regexp tramp-action-yn)
                              (tramp-terminal-prompt-regexp
                               tramp-action-terminal)
                              )
 tramp-multi-actions '((tramp-password-prompt-regexp
                        tramp-multi-action-password)
                       (tramp-login-prompt-regexp tramp-multi-action-login)
                       (shell-prompt-pattern tramp-multi-action-succeed)
                       (tramp-shell-prompt-pattern tramp-multi-action-succeed)
                       (tramp-wrong-passwd-regexp
                        tramp-multi-action-permission-denied)
                       )
 tramp-terminal-type "dumb"
 tramp-shell-prompt-pattern "^[^#$%>\n]*[#$%>] *\\(\\[[0-9;]*[a-zA-Z] *\\)*"
 tramp-chunksize nil
 shell-prompt-pattern "^[^#$%>\n]*[#$%>] *"
 backup-by-copying nil
 backup-by-copying-when-linked nil
 backup-by-copying-when-mismatch nil
 backup-by-copying-when-privileged-mismatch 200
 file-name-handler-alist '(("^/[^/]*$" . tramp-completion-file-name-handler)
                           ("\\`/[^/:]+:" . tramp-file-name-handler)
                           ("\\`/:" . file-name-non-special))
 )

----- *debug tramp/ssh2 address@hidden ------
# Opening connection for address@hidden using ssh2...
# Waiting for prompts from remote shell
# Waiting 60s for prompt from remote shell
# Sending password
# Found remote shell prompt.
# Initializing remote shell
----- *debug tramp/ssh2 address@hidden -----------
# Opening connection for address@hidden using ssh2...
# Waiting for prompts from remote shell
# Waiting 60s for prompt from remote shell
# Permission denied by remote host.
----- *tramp/ssh2 localhost* ---------------------
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that the DSA host key has just been changed.
The fingerprint for the DSA key sent by the remote host is
cc:1e:c0:12:05:ea:d8:1c:55:d5:5d:cf:bb:d1:ce:20.
Please contact your system administrator.
Add correct host key in /home/fer/.ssh/known_hosts to get rid of this message.
Offending key in /home/fer/.ssh/known_hosts:1
DSA host key for localhost has changed and you have requested strict checking.
Host key verification failed.

Process *tramp/ssh2 localhost* exited abnormally with code 255
---- *Messages* ------------------------------------
tramp: Opening connection for address@hidden using ssh2...
tramp: Waiting for prompts from remote shell
tramp: Waiting 60s for prompt from remote shell
tramp: Sending password
Password: 
Password: .
Password: ..
Password: .........
tramp: Found remote shell prompt.
tramp: Initializing remote shell
tramp: Opening connection for address@hidden using ssh2...
tramp: Waiting for prompts from remote shell
tramp: Waiting 60s for prompt from remote shell
tramp: Permission denied by remote host.
if: Login failed
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