<div dir="ltr"><div>Hi.</div><div>Output of netstat command made me think.</div><div>Let' s look:</div><div> </div><div>tcp 0 0 <a href="http://127.0.0.1:5038">127.0.0.1:5038</a> 0.0.0.0:* LISTEN 27158/asterisk<br>tcp 0 0 <a href="http://0.0.0.0:80">0.0.0.0:80</a> 0.0.0.0:* LISTEN 911/apache2<br>tcp 0 0 <a href="http://10.10.0.254:82">10.10.0.254:82</a> 0.0.0.0:* LISTEN 911/apache2<br>tcp 0 0 <a href="http://127.0.0.1:82">127.0.0.1:82</a> 0.0.0.0:* LISTEN 911/apache2<br>tcp 0 0 <a href="http://10.10.0.254:53">10.10.0.254:53</a> 0.0.0.0:* LISTEN 2167/named<br>tcp 0 0 <a href="http://127.0.0.1:53">127.0.0.1:53</a> 0.0.0.0:* LISTEN 2167/named<br>tcp 0 0 <a href="http://10.10.0.254:5432">10.10.0.254:5432</a> 0.0.0.0:* LISTEN 1635/postgres<br>tcp 0 0 <a href="http://127.0.0.1:5432">127.0.0.1:5432</a> 0.0.0.0:* LISTEN 1635/postgres<br>tcp 0 0 <a href="http://127.0.0.1:953">127.0.0.1:953</a> 0.0.0.0:* LISTEN 2167/named<br>tcp 0 0 <a href="http://127.0.0.1:5432">127.0.0.1:5432</a> <a href="http://127.0.0.1:59125">127.0.0.1:59125</a> ESTABLISHED 27198/postgres: ast<br>tcp 0 0 <a href="http://127.0.0.1:59125">127.0.0.1:59125</a> <a href="http://127.0.0.1:5432">127.0.0.1:5432</a> ESTABLISHED 27158/asterisk<br>udp 0 0 <a href="http://0.0.0.0:5060">0.0.0.0:5060</a> 0.0.0.0:* 27158/asterisk<br>udp 0 0 <a href="http://127.0.0.1:41958">127.0.0.1:41958</a> <a href="http://127.0.0.1:41958">127.0.0.1:41958</a> ESTABLISHED 1635/postgres<br><strong>udp 0 0 <a href="http://0.0.0.0:40895">0.0.0.0:40895</a> 0.0.0.0:* 12116/dhcpd</strong><br>udp 0 0 <a href="http://10.10.0.254:53">10.10.0.254:53</a> 0.0.0.0:* 2167/named<br>udp 0 0 <a href="http://127.0.0.1:53">127.0.0.1:53</a> 0.0.0.0:* 2167/named<br><strong>udp 0 0 <a href="http://0.0.0.0:67">0.0.0.0:67</a> 0.0.0.0:* 12116/dhcpd</strong><br>udp 125440 0 <a href="http://0.0.0.0:68">0.0.0.0:68</a> 0.0.0.0:* 10681/charon<br>udp 0 0 <a href="http://10.10.0.254:123">10.10.0.254:123</a> 0.0.0.0:* 1290/ntpd<br>udp 0 0 <a href="http://127.0.0.1:123">127.0.0.1:123</a> 0.0.0.0:* 1290/ntpd<br><strong>udp6 0 0 :::39873 :::* 12116/dhcpd<br></strong></div><div> </div><div> </div><div>I will try to change grubconf.</div><div>But I turned off IPv6 completely by sysctl.d.</div><div> </div><div>With wishes of many good things.</div></div><div class="gmail_extra"><br><div class="gmail_quote">2016-03-17 15:39 GMT+03:00 Nicolas C. <span dir="ltr"><<a href="mailto:dhcp@nryc.fr" target="_blank">dhcp@nryc.fr</a>></span>:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="HOEnZb"><div class="h5">Le 16/03/2016 23:05, CpServiceSPb . a écrit :<br>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;padding-left:1ex;border-left-color:rgb(204,204,204);border-left-width:1px;border-left-style:solid">
I have isc-dhcp-server installed at ubuntu 14.04 x64.<br>
Its version is 4.2.4<br>
I have fully disabled IPv6 at OS.<br>
Also I have "-4" option for dhcp server startup.<br>
But there is one IPv6 listened address by netstat -anupt.<br>
Port is dyynamic.<br>
What is this dynamically defined port intended for ?<br>
And how is to fully disable IPv6 listening ?<br>
</blockquote>
<br></div></div>
Hello,<br>
<br>
What makes you think that this is caused by the DHCP server? Can you give us the output of your "netstat" command? Is the dhcpd service listening to an IPv6 address? Maybe a "ps -ef | grep dhcpd" will give us a hint.<br>
<br>
Try disabling IPv6 by adding "ipv6.disable=1" on the GRUB_CMDLINE_LINUX_DEFAULT variable in the /etc/default/grub file, then run "update-grub" and reboot. But there's little chance that the DHCP server has anything to do with your problem because it is not dual-stack : it can operate only for one protocol at the time (DHCPv4 *or* DHCPv6).<br>
<br>
Have a nice day,<br>
</blockquote></div><br></div>