[gentoo-user] SSH authentication attempts - serious issue

[Leandro Melo de Sales]

Hi,

   today when I was checking the server log I got many external
attempts to connect to my sshd service:

...
Jun  5 05:09:45 embedded sshd[4740]: Invalid user barbara from x.y.w.z
Jun  5 05:09:46 embedded sshd[4742]: Invalid user barb from x.y.w.z
Jun  5 05:09:48 embedded sshd[4744]: Invalid user barbie from x.y.w.z
Jun  5 05:09:50 embedded sshd[4746]: Invalid user barbra from x.y.w.z
Jun  5 05:09:51 embedded sshd[4748]: Invalid user barman from x.y.w.z
Jun  5 05:09:53 embedded sshd[4750]: Invalid user barney from x.y.w.z
...

this seems to be a brute force attack, but one thing that worried me
is why sshd didn't disconnect the remote host after 3 unsuccessful
attemps? If we see in the log, there are many attemps with time
interval between attemps of 2 or 3 seconds meaning that the sshd
didn't disconnect the remote host after 3 attempts.
 So, first, Am I thinking correct about the sshd attempts?
 Second, how can I setup sshd or the entire system to permit just 2 or
3 attempts of authentication? I was checking the /etc/login.defs file
and I see the following option:

#
# Max number of login retries if password is bad
#
LOGIN_RETRIES           3

but why this didn't work for the above connection attempts?

Thank you,

Leandro.
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