warning: /etc/hosts.allow, line xx: host name/name mismatch

Question

I am using CLION in Mac OSX High Sierra, and when I compile, I have an error.

 cadena=static_cast<ostringstream*>(&(ostringstream()<<vidas))->str();

and the error is:

/Users/macbookpro-jonathanprieto/CLionProjects/xonixpacman/main.cpp:113:40: error: cannot take the address of an rvalue of type 'std::__1::basic_ostringstream, std::__1::allocator >' cadena=static_cast(&(ostringstream()<str();

Solution

sshd is just giving you a warning that the denied connection is not listed in either hosts.allow or hosts.deny, this is part of the verbose logging behavior, allowing you to troubleshoot connections which might need to be matched, and aren't matching (usually due to to incorrectly configured DNS entries, especially RDNS entries).

Keeping an eye on warnings is never a bad idea though, although this is fairly innocuous.

Comments

[molbdnilo]

Well, you can't take the address of an rvalue. What exactly do you want to accomplish?

[Nishanth]

my rdns/dns mapping is setup correctly, *.aliyun.com does not belong to me, its an attacker

[NickW]

Looking into it further, it's basically saying that the connection does not respond to a line in either the hosts.allow, or in hosts.deny. You're doing verbose logging, which is useful to identify problems like the one I mentioned before.

[NickW]

Furthermore, it's logging to allow you to see why a certain user is being denied (or not allowed) access. Obviously the connections that aren't being logged are already matching a line in one of the two files.

[Nishanth]

My DSL dynamic IP/Hostname is not in hosts.allow too and it does not log any warning. I don't understand why sshd wants the attackers hostname to match my local hostname, this can't be

[NickW]

There is the misunderstanding, it doesn't "want" anything, it is just trying to let you know that this connection came through, and was denied, but since the IP wasn't listed in either file, it might be something you want to change (you might be troubleshooting someone unable to connect). It's just a side effect of verbose logging.

[Nishanth]

That might be it. Well many people ignore warnings in common but I really want to investigate them and understand. If you edit your answer I'm gonna accept it, tyvm.

[NickW]

Certainly, it's good seeing people making sure they understand what the programs are logging.

[Jonathan Prieto]

You put vidas as a word but I need it as a variable !

[Gem Taylor]

Disaster! I didn't have a variable called vidas. :-) So change #std::string("vidas")# back to #vidas#