Messages in this thread | | | Date | Sat, 1 Oct 2011 20:34:48 +0200 | From | Willy Tarreau <> | Subject | Re: kernel.org status: hints on how to check your machine for intrusion |
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On Sat, Oct 01, 2011 at 02:29:22PM -0400, Steven Rostedt wrote: > On Sat, 2011-10-01 at 14:13 -0400, David Miller wrote: > > From: Steven Rostedt <rostedt@goodmis.org> > > Date: Sat, 1 Oct 2011 14:06:41 -0400 > > > > > For my machine that is connected to the outside world, I have a script > > > that runs every night that checks for attacks. As bots constantly look > > > for port 22 and 80, they find my machine without issue. When my script > > > detects a bunch of ssh login attempts that fail, it will add that ip > > > address to the iptables DROP chain: > > > > By running sshd on a different port, you'll avoid the login attempts > > as well as the overhead of the successful connection attempts. > > > > I haven't allowed sshd to run on port 22 in more than 10 years. > > I use to do that a long time ago, but I ran into issues because of it. > Can't remember the exact problem. Maybe it was places I went to that did > not allow outgoing connections to non official ports. Whatever it was, > it was annoying enough to put sshd back to 22.
443 is pretty nice for connecting from unexpected places ;-)
> I probably can go back to a non 22 port without much issue. I have added > a bunch of personal checks to this box that gives a report every day. I > may add more (from what was posted in this thread already). I also have > logwatch and rkhunter running, and just added chkrootkit now. > > But moving the ssh port again may be a good idea. But I like stressing > your net filtering code ;)
BTW ipset is particularly suited for this.
Regards, Willy
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