Re: [bitfolk] Reverse Mapping Checking Failed In auth.log

Hi Sam, On Mon, Apr 08, 2013 at 12:22:27PM +0200, Samuel Bächler wrote: Not quite. The reverse of 193.231.42.110 is isjhr-nxt.eduhr.ro: $ dig +noall +answer -x 193.231.42.110 110.42.231.193.in-addr.arpa. 10731 IN PTR ISJhr-nxt.eduhr.ro. But there is no matching A or AAAA record for ISJhr-nxt.eduhr.ro: $ dig +noall +answer -t a ISJhr-nxt.eduhr.ro $ dig +noall +answer -t aaaa ISJhr-nxt.eduhr.ro $ Bear in mind that the two parts of the DNS here are often under the control of two different sets of people. For example, as a BitFolk customer you can set your reverse DNS to whatever you like, say fbi.gov. But since you (probably) have no access to fbi.gov DNS zone you cannot add matching A/AAAA records that point to your VPS. sshd is warning you not to believe the supplied "ISJhr-nxt.eduhr.ro" because lacking the matching A/AAAA records it is possible that they just made it up in the hope that you have some sort of DNS-based access control. SSH access control doesn't work like that so you don't need to worry about that. Yes, and it is an invalid user presumably because that user does not exist on your VPS. Yes, unless they guess a user name that does exist and that user name belongs to someone who may set a weak password. Cheers, Andy -- http://bitfolk.com/ -- No-nonsense VPS hosting Provides seating. — Andy Davidson