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Groups > linux.debian.user > #163162

Re: DenyHosts

From Reco <recoverym4n@gmail.com>
Newsgroups linux.debian.user
Subject Re: DenyHosts
Date 2016-01-16 18:20 +0100
Message-ID <qRCG6-7ja-7@gated-at.bofh.it> (permalink)
References <qRkga-3k6-13@gated-at.bofh.it> <qRCwq-7e6-21@gated-at.bofh.it>
Organization linux.* mail to news gateway

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	Hi.

On Sat, 16 Jan 2016 12:02:57 -0500
Steve Matzura <sm@noisynotes.com> wrote:

> Well, I thought I was doing so well. I discover now that no one,
> including me, can get into my system any more via ssh. Here are the
> current iptables rules:
> 
> *filter
> :INPUT ACCEPT [0:0]
> :FORWARD ACCEPT [0:0]
> :OUTPUT ACCEPT [0:0]
> -A INPUT -p tcp -m tcp --dport 22 --tcp-flags SYN,RST,ACK SYN -j DROP
> -A INPUT -p tcp -m tcp --dport 22 -m conntrack --ctstate NEW -m
> hashlimit --hashlimit-upto 1/hour --hashlimit-burst 16
> --hashlimit-mode srcip --hashlimit-name ssh --hashlimit-htable-expire
> 60000 -j ACCEPT
> -A INPUT -p tcp -m tcp --dport 22 --tcp-flags SYN,RST,ACK SYN -j DROP
> -A INPUT -p tcp -m tcp --dport 22 -m conntrack --ctstate NEW -m
> hashlimit --hashlimit-upto 1/hour --hashlimit-burst 16
> --hashlimit-mode srcip --hashlimit-name ssh --hashlimit-htable-expire
> 60000 -j ACCEPT
> -A INPUT -p tcp -m tcp --dport 22 --tcp-flags SYN,RST,ACK SYN -j DROP
> -A INPUT -p tcp -m tcp --dport 22 -m conntrack --ctstate NEW -m
> hashlimit --hashlimit-upto 1/hour --hashlimit-burst 16
> --hashlimit-mode srcip --hashlimit-name ssh --hashlimit-htable-expire
> 60000 -j ACCEPT
> -A INPUT -p tcp -m tcp --dport 22 --tcp-flags SYN,RST,ACK SYN -j DROP
> -A INPUT -p tcp -m tcp --dport 22 -m conntrack --ctstate NEW -m
> hashlimit --hashlimit-upto 1/hour --hashlimit-burst 16
> --hashlimit-mode srcip --hashlimit-name ssh --hashlimit-htable-expire
> 60000 -j ACCEPT
> -A INPUT -p tcp -m tcp --dport 22 --tcp-flags SYN,RST,ACK SYN -j DROP
> -A INPUT -p tcp -m tcp --dport 22 -m conntrack --ctstate NEW -m
> hashlimit --hashlimit-upto 1/hour --hashlimit-burst 16
> --hashlimit-mode srcip --hashlimit-name ssh --hashlimit-htable-expire
> 60000 -j ACCEPT
> -A INPUT -p tcp -m tcp --dport 22 --tcp-flags SYN,RST,ACK SYN -j DROP
> -A INPUT -p tcp -m tcp --dport 22 --tcp-flags SYN,RST,ACK SYN -j DROP
> -A INPUT -p tcp -m tcp --dport 22 -m conntrack --ctstate NEW -m
> hashlimit --hashlimit-upto 1/hour --hashlimit-burst 16
> --hashlimit-mode srcip --hashlimit-name ssh --hashlimit-htable-expire
> 60000 -j ACCEPT
> COMMIT
> 
> What'd I do?
> 

Exactly this:

iptables -F INPUT
iptables -I INPUT -p tcp --dport 22 -m conntrack --ctstate NEW \
	-m hashlimit --hashlimit 1/hour --hashlimit-burst 16 \
	--hashlimit-mode srcip --hashlimit-name ssh \
	--hashlimit-htable-expire 60000 -j ACCEPT
iptables -I INPUT -p tcp --dport 22 --tcp-flags SYN,RST,ACK SYN \
	-j DROP

Note that the order of netfilter rules is top-down (i.e. highest
matching rule plays).
So, first rule on your current list, namely:

-A INPUT -p tcp -m tcp --dport 22 --tcp-flags SYN,RST,ACK SYN -j DROP

blocked anyone from using ssh.

Reco

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Thread

DenyHosts Steve Matzura <sm@noisynotes.com> - 2016-01-15 22:40 +0100
  Re: DenyHosts Sven Arvidsson <sa@whiz.se> - 2016-01-15 22:50 +0100
  Re: DenyHosts "Cláudio E. Elicker" <elicker@gmail.com> - 2016-01-15 23:10 +0100
  Re: DenyHosts Reco <recoverym4n@gmail.com> - 2016-01-16 00:00 +0100
    Re: DenyHosts Steve Matzura <sm@noisynotes.com> - 2016-01-16 05:50 +0100
      Re: DenyHosts David <bouncingcats@gmail.com> - 2016-01-16 06:50 +0100
        Re: DenyHosts Chris Bannister <cbannister@slingshot.co.nz> - 2016-01-17 06:50 +0100
    Re: DenyHosts Steve Matzura <sm@noisynotes.com> - 2016-01-16 06:00 +0100
    Re: DenyHosts Steve Matzura <number6@noisynotes.com> - 2016-01-16 07:10 +0100
      Re: DenyHosts Reco <recoverym4n@gmail.com> - 2016-01-16 11:00 +0100
        Re: DenyHosts Steve Matzura <number6@noisynotes.com> - 2016-01-16 14:00 +0100
          Re: DenyHosts Reco <recoverym4n@gmail.com> - 2016-01-16 14:20 +0100
            Re: DenyHosts Steve Matzura <sm@noisynotes.com> - 2016-01-16 19:10 +0100
              Re: DenyHosts Reco <recoverym4n@gmail.com> - 2016-01-16 22:00 +0100
                Re: DenyHosts Steve Matzura <number6@noisynotes.com> - 2016-01-16 22:30 +0100
        Re: DenyHosts Christian Seiler <christian@iwakd.de> - 2016-01-17 14:10 +0100
          Re: DenyHosts Moreanu Robert - Nicolae <robertmoreanu@gmail.com> - 2016-01-17 14:40 +0100
            Re: DenyHosts Bob Holtzman <holtzm@cox.net> - 2016-01-17 22:50 +0100
          Re: DenyHosts Igor Cicimov <icicimov@gmail.com> - 2016-01-17 14:40 +0100
  Re: DenyHosts Steve Matzura <sm@noisynotes.com> - 2016-01-16 18:10 +0100
    Re: DenyHosts Reco <recoverym4n@gmail.com> - 2016-01-16 18:20 +0100
      Re: DenyHosts Steve Matzura <number6@noisynotes.com> - 2016-01-16 19:10 +0100
        Re: DenyHosts Reco <recoverym4n@gmail.com> - 2016-01-16 21:50 +0100
          Re: DenyHosts Steve Matzura <number6@noisynotes.com> - 2016-01-16 22:40 +0100

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