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-   -   ssh login reverse mapping failed, should I worry? (https://www.linuxquestions.org/questions/linux-security-4/ssh-login-reverse-mapping-failed-should-i-worry-370303/)

michaelsanford 10-06-2005 08:50 AM
ssh login reverse mapping failed, should I worry?
 
Code:
Address 67.71.152.11 maps to 10.152.71.61.in-addr.arpa, but this
does not map back to the address - POSSIBLE BREAKIN ATTEMPT!
I just got this when logging in to my Slackware box from my campus wifi (first time I've used the campus wifi, new system). Could that be the culprit?

PS 67.71.152.11 is the address of my server as reported by ifconfig | grep ppp0.

TruckStuff 10-06-2005 04:44 PM
It just means that the reverse DNS for your campus wifi is not properly configured and SSH could not determine a hostname for the IP in question. Personally, I don't know why SSH gripes about this, but I'm sure there is a (somewhat) legitimate reason somewhere.

ppuru 10-06-2005 05:34 PM
From the sshd_config manpages
Quote:
UseDNS Specifies whether sshd should lookup the remote host name
and check that the resolved host name for the remote IP
address maps back to the very same IP address.
The default is "yes"

michaelsanford 10-16-2005 09:27 AM
I had a feeling it was UseDNS, but I'm never sure whether it's the sshd or ssh that outputs those messages (i.e., I wasn't totally sure whether it was my end or the server end that was complaining about the DNS entry being wrong).

Thanks.


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