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Re: (OT kinda) Newly-discovered TCP flaw

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Joe wrote:

> On Thu, 11 Aug 2016 20:31:37 +0100
> Lisi Reisz <lisi.reisz@gmail.com> wrote:
> 
> 
>> 
>> I copied and pasted the commands exactly, and ran them as root, and
>> got an echo of net.ipv4.tcp_challenge_ack_limit = 999999999 in
>> response to the first and a blank return in response to the second.
>> I don't know the significance.
>> 
> 
> Go and read /proc/net/ipv4... and it should show the changed value.
> 
> I believe the echo means it worked. I also believe it needs to be added
> to /etc/sysctl.conf (without the 'sysctl -p') to be redone on boot. It
> seems to affect every current Debian up to sid.

I don't see it in the /proc tree (kernel 4.6.4 on jessie)
 
# ls -1 /proc/net/ip*
/proc/net/ip6_flowlabel
/proc/net/ip_tables_matches
/proc/net/ip_tables_names
/proc/net/ip_tables_targets
/proc/net/ipv6_route

and on the firewall (2.6.26.2 wheezy)

 sysctl -w net.ipv4.tcp_challenge_ack_limit=999999999
sysctl: cannot stat /proc/sys/net/ipv4/tcp_challenge_ack_limit: No such file
or directory

I don't understand if it is bad.

on the file server (kernel 3.2.0 jessie)

cat /proc/sys/net/ipv4/tcp_challenge_ack_limit
999999999

interesting ...

Do you have recommendations?

regards

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Thread

(OT kinda) Newly-discovered TCP flaw Curt <curty@free.fr> - 2016-08-11 18:00 +0200
  Re: (OT kinda) Newly-discovered TCP flaw Reco <recoverym4n@gmail.com> - 2016-08-11 18:30 +0200
    Re: (OT kinda) Newly-discovered TCP flaw Curt <curty@free.fr> - 2016-08-11 18:50 +0200
      Re: (OT kinda) Newly-discovered TCP flaw Hugo Vanwoerkom <hvw59601@care2.com> - 2016-08-12 23:40 +0200
        Re: (OT kinda) Newly-discovered TCP flaw Curt <curty@free.fr> - 2016-08-13 11:10 +0200
          Re: (OT kinda) Newly-discovered TCP flaw Reco <recoverym4n@gmail.com> - 2016-08-13 11:20 +0200
            Re: (OT kinda) Newly-discovered TCP flaw Curt <curty@free.fr> - 2016-08-13 17:20 +0200
          Re: (OT kinda) Newly-discovered TCP flaw Pascal Hambourg <pascal@plouf.fr.eu.org> - 2016-08-13 11:20 +0200
            Re: (OT kinda) Newly-discovered TCP flaw Curt <curty@free.fr> - 2016-08-13 17:20 +0200
        Re: (OT kinda) Newly-discovered TCP flaw Reco <recoverym4n@gmail.com> - 2016-08-13 11:20 +0200
  Re: (OT kinda) Newly-discovered TCP flaw Gene Heskett <gheskett@shentel.net> - 2016-08-11 18:40 +0200
    Re: (OT kinda) Newly-discovered TCP flaw Gene Heskett <gheskett@shentel.net> - 2016-08-11 19:00 +0200
      Re: (OT kinda) Newly-discovered TCP flaw Curt <curty@free.fr> - 2016-08-11 19:30 +0200
    Re: (OT kinda) Newly-discovered TCP flaw Dan Ritter <dsr@randomstring.org> - 2016-08-11 19:00 +0200
    Re: (OT kinda) Newly-discovered TCP flaw Nicolas George <george@nsup.org> - 2016-08-11 19:10 +0200
      Re: (OT kinda) Newly-discovered TCP flaw Gene Heskett <gheskett@shentel.net> - 2016-08-11 20:00 +0200
        Re: (OT kinda) Newly-discovered TCP flaw Doug <dmcgarrett@optonline.net> - 2016-08-11 20:50 +0200
          Re: (OT kinda) Newly-discovered TCP flaw Gene Heskett <gheskett@shentel.net> - 2016-08-11 21:10 +0200
            Re: (OT kinda) Newly-discovered TCP flaw Lisi Reisz <lisi.reisz@gmail.com> - 2016-08-11 21:40 +0200
              Re: (OT kinda) Newly-discovered TCP flaw Joe <joe@jretrading.com> - 2016-08-11 22:10 +0200
                Re: (OT kinda) Newly-discovered TCP flaw deloptes <deloptes@gmail.com> - 2016-08-11 22:40 +0200
                Re: (OT kinda) Newly-discovered TCP flaw Joe <joe@jretrading.com> - 2016-08-11 22:50 +0200
                Re: (OT kinda) Newly-discovered TCP flaw deloptes <deloptes@gmail.com> - 2016-08-12 00:00 +0200
                Re: (OT kinda) Newly-discovered TCP flaw Bob Weber <bobrweber@gmail.com> - 2016-08-12 00:00 +0200
                Re: (OT kinda) Newly-discovered TCP flaw Curt <curty@free.fr> - 2016-08-12 11:00 +0200
                Re: (OT kinda) Newly-discovered TCP flaw Gene Heskett <gheskett@shentel.net> - 2016-08-12 12:00 +0200
                Re: (OT kinda) Newly-discovered TCP flaw deloptes <deloptes@gmail.com> - 2016-08-12 12:50 +0200
                Re: (OT kinda) Newly-discovered TCP flaw Gene Heskett <gheskett@shentel.net> - 2016-08-12 13:30 +0200
                Re: (OT kinda) Newly-discovered TCP flaw deloptes <deloptes@gmail.com> - 2016-08-12 22:30 +0200
                Re: (OT kinda) Newly-discovered TCP flaw Curt <curty@free.fr> - 2016-08-12 14:30 +0200
                Re: (OT kinda) Newly-discovered TCP flaw rhkramer@gmail.com - 2016-08-12 16:50 +0200
                Re: (OT kinda) Newly-discovered TCP flaw Greg Wooledge <wooledg@eeg.ccf.org> - 2016-08-12 17:00 +0200
                Re: (OT kinda) Newly-discovered TCP flaw Pascal Hambourg <pascal@plouf.fr.eu.org> - 2016-08-12 17:20 +0200
                Re: (OT kinda) Newly-discovered TCP flaw Greg Wooledge <wooledg@eeg.ccf.org> - 2016-08-12 17:40 +0200
                Re: (OT kinda) Newly-discovered TCP flaw rhkramer@gmail.com - 2016-08-12 17:40 +0200
                Re: (OT kinda) Newly-discovered TCP flaw "John L. Ries" <jries@salford-systems.com> - 2016-08-12 18:40 +0200
                Re: (OT kinda) Newly-discovered TCP flaw Curt <curty@free.fr> - 2016-08-12 18:10 +0200
                Re: (OT kinda) Newly-discovered TCP flaw Gene Heskett <gheskett@shentel.net> - 2016-08-12 18:00 +0200
                The Debian/Ubuntu/Mint installer was Re: (OT kinda) Newly-discovered TCP flaw Lisi Reisz <lisi.reisz@gmail.com> - 2016-08-13 01:10 +0200
                Re: The Debian/Ubuntu/Mint installer was Re: (OT kinda) Newly-discovered TCP flaw Gene Heskett <gheskett@shentel.net> - 2016-08-13 05:20 +0200
                Re: The Debian/Ubuntu/Mint installer was Re: (OT kinda) Newly-discovered TCP flaw Lisi Reisz <lisi.reisz@gmail.com> - 2016-08-13 10:50 +0200
                Re: (OT kinda) Newly-discovered TCP flaw Gene Heskett <gheskett@shentel.net> - 2016-08-12 05:00 +0200
              Re: (OT kinda) Newly-discovered TCP flaw Gene Heskett <gheskett@shentel.net> - 2016-08-12 04:50 +0200

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