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<p>Hi all,</p>
<p>thanks for your answers! <br>
</p>
<p>Cheers, <br>
</p>
<p>Jakob<br>
</p>
<br>
<div class="moz-cite-prefix">On 10.12.18 15:56, Tony Finch wrote:<br>
</div>
<blockquote type="cite"
cite="mid:alpine.DEB.2.20.1812101453190.2562@grey.csi.cam.ac.uk">
<pre wrap="">Warren Kumari <a class="moz-txt-link-rfc2396E" href="mailto:warren@kumari.net"><warren@kumari.net></a> wrote:
</pre>
<blockquote type="cite">
<pre wrap="">I’m also wondering *how* it is doing this — to increment by 2 it sounds
like there is state being kept - perhaps dig simply relies on the kernel
for the source port and isn’t randomizing at all ( and so the difference is
actually OS difference, and not dig differences?
</pre>
</blockquote>
<pre wrap="">
Yes. It's also a protocol family difference, because Mac OS does randomize
over IPv4. (Not doing so over IPv6 must be a bug....)
There are sysctls:
net.inet.tcp.randomize_ports: 0
net.inet.udp.randomize_ports: 1
The net.inet sysctls for UDP and TCP should also apply to inet6...
Tony.
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<pre class="moz-signature" cols="72">--
SWITCH
Jakob Dhondt, Security Engineer, SWITCH-CERT
Werdstrasse 2, P.O. Box, 8021 Zurich, Switzerland
phone +41 44 268 15 15, direct +41 44 268 16 23
<a class="moz-txt-link-abbreviated" href="mailto:jakob.dhondt@switch.ch">jakob.dhondt@switch.ch</a>, <a class="moz-txt-link-abbreviated" href="http://www.switch.ch">www.switch.ch</a>
Security-News: securityblog.switch.ch</pre>
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