[SOLVED] rsh/ssh problem: POSSIBLE BREAK-IN ATTEMPT, most probably due to DNS configuration
Linux - NewbieThis Linux forum is for members that are new to Linux.
Just starting out and have a question?
If it is not in the man pages or the how-to's this is the place!
Notices
Welcome to LinuxQuestions.org, a friendly and active Linux Community.
You are currently viewing LQ as a guest. By joining our community you will have the ability to post topics, receive our newsletter, use the advanced search, subscribe to threads and access many other special features. Registration is quick, simple and absolutely free. Join our community today!
Note that registered members see fewer ads, and ContentLink is completely disabled once you log in.
If you have any problems with the registration process or your account login, please contact us. If you need to reset your password, click here.
Having a problem logging in? Please visit this page to clear all LQ-related cookies.
Get a virtual cloud desktop with the Linux distro that you want in less than five minutes with Shells! With over 10 pre-installed distros to choose from, the worry-free installation life is here! Whether you are a digital nomad or just looking for flexibility, Shells can put your Linux machine on the device that you want to use.
Exclusive for LQ members, get up to 45% off per month. Click here for more info.
rsh/ssh problem: POSSIBLE BREAK-IN ATTEMPT, most probably due to DNS configuration
Good afternoon,
On a HP server, I am running Linux Red Hat 5.
I have an application that launches "rsh PSMF" or "ssh PSMF" in background, which goes wrong: the entry "PSMF" is created in the file "/etc/hosts" and the corresponding IP address is found, but there seems to be a mismatch in the other way, as can be seen in following excerpt:
smf1 linus> rsh -v PSMF
OpenSSH_4.3p2, OpenSSL 0.9.8e-fips-rhel5 01 Jul 2008
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug1: Applying options for *
debug1: Connecting to PSMF [xxx.xxx.xxx.xxx] port 22.
debug1: Connection established.
debug1: identity file /osp/local/home/linus/.ssh/id_rsa type 1
debug1: identity file /osp/local/home/linus/.ssh/id_dsa type -1
debug1: loaded 2 keys
debug1: Remote protocol version 2.0, remote software version OpenSSH_4.3
debug1: match: OpenSSH_4.3 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_4.3
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client aes128-ctr hmac-md5 none
debug1: kex: client->server aes128-ctr hmac-md5 none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug1: Host 'psmf' is known and matches the RSA host key.
debug1: Found key in /osp/local/home/linus/.ssh/known_hosts:1
debug1: ssh_rsa_verify: signature correct
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey,gssapi-with-mic,password
debug1: Next authentication method: gssapi-with-mic Address xxx.xxx.xxx.xxx maps to smf1, but this does not map back to the address - POSSIBLE BREAK-IN ATTEMPT!
debug1: Unspecified GSS failure. Minor code may provide more information
Unknown code krb5 195
debug1: Unspecified GSS failure. Minor code may provide more information
Unknown code krb5 195
debug1: Unspecified GSS failure. Minor code may provide more information
Unknown code krb5 195
debug1: Next authentication method: publickey
debug1: Offering public key: /osp/local/home/linus/.ssh/id_rsa
debug1: Server accepts key: pkalg ssh-rsa blen 277
debug1: read PEM private key done: type RSA
debug1: Authentication succeeded (publickey).
debug1: channel 0: new [client-session]
debug1: Entering interactive session.
debug1: Sending environment.
debug1: Sending env LANG = C
Last login: Tue Jan 3 17:31:27 2012 from xxx.xxx.xxx.xxx
[1] 2916
End of linus profile
I have been looking on the internet and it seems that a wrong DNS configuration might be causing this issue. Unfortunately I don't know how to verify my DNS configuration and even then, I don't know how to interpret the "rsh -v" output.
(As there seems to be a security issue, I have blanked out the IP address (xxx.xxx.xxx.xxx), but I confirm that it is correct.)
debug1: Authentications that can continue: publickey,gssapi-with-mic,password
debug1: Next authentication method: gssapi-with-mic
Address xxx.xxx.xxx.xxx maps to smf1, but this does not map back to the address - POSSIBLE BREAK-IN ATTEMPT!
debug1: Unspecified GSS failure. Minor code may provide more information
Unknown code krb5 195
If 'ssh -o GSSAPIAuthentication no PSMF' doesn't produce those lines try disabling anything GSSAPI in your configuration?
Thanks for the fast reply.
I have launched the mentioned command and I get the following:
ssh -o GSSAPIAuthentication no PSMF
command-line line 0: Missing yes/no argument.
When you write about disabling GSSAPI, how can I do this (I know, I'm a newbie)?
Thanks
Dominique
ssh -o GSSAPIAuthentication no PSMF
command-line line 0: Missing yes/no argument.
Sorry, should be 'ssh -o GSSAPIAuthentication=no PSMF'.
Quote:
Originally Posted by scampsd
When you write about disabling GSSAPI, how can I do this
If you have one, your personal ~/.ssh/config may list defaults for all connections. To tweak just one connection add a section (below what's there already):
LinuxQuestions.org is looking for people interested in writing
Editorials, Articles, Reviews, and more. If you'd like to contribute
content, let us know.