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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>If setup is connected in L2-Switch, use VLAN, ensure client broadcast messages should not hit directly to server. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Regards<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Arun.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> arunprasad [mailto:arunprasad@pointred.co] <br><b>Sent:</b> Wednesday, April 18, 2012 4:35 PM<br><b>To:</b> 'Users of ISC DHCP'<br><b>Subject:</b> RE: DHCP Relay: Duplicate packets for DHCPRELEASE and DHCPREQUEST<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Hi Sujitha,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Try keeping DHCP-Server & DHCP-relay in different subnet.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Regards<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Arun.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> dhcp-users-bounces+arunprasad=pointred.co@lists.isc.org [mailto:dhcp-users-bounces+arunprasad=pointred.co@lists.isc.org] <b>On Behalf Of </b>Sujata Verma<br><b>Sent:</b> Wednesday, April 18, 2012 4:16 PM<br><b>To:</b> Users of ISC DHCP<br><b>Subject:</b> Re: DHCP Relay: Duplicate packets for DHCPRELEASE and DHCPREQUEST<o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p><table class=MsoNormalTable border=0 cellspacing=0 cellpadding=0><tr><td valign=top style='padding:0in 0in 0in 0in'><p class=MsoNormal>Thanks for reply.<br><br>My setup is like this : <br> eth1<br> Windows 2003 server ( 192.168.9.2/23)-------------------(192.168.8.177/23) Linux PC(Relay) (80.1.1.1/24----------eth0----Windows XP Client ( DHCP client getting IP 80.1.1.2/24)<br><br>In windows server the default gw is 192.168.8.177. The DHCP pool configured gateway is 80.1.1.1 ( relay agent ip) <br><br>I am attaching the wireshark capture for both client and server. In this we can see that the DHCPDISCOVER is only being sent once to the server which relay is forwarding while adding giaddr field as 80.1.1.1 . <br><br>When DHCPRELEASE packet is being sent, it is sent directly to the server and with other two packets as duplicates with giaddr as of two interfaces. <br><br>In linux pc i have only enabled ipv4_forward and disabled iptables completely. Is there any other configuration which can result in my observation like this ?<br><br>Please let me know your observations, after seeing the captures. I have tried many times with similar observation.<br><br>Regards,<br>Sujata<br> <br>--- On <b>Wed, 4/18/12, Simon Hobson <i><<a href="mailto:dhcp1@thehobsons.co.uk">dhcp1@thehobsons.co.uk</a>></i></b> wrote:<o:p></o:p></p><p class=MsoNormal style='margin-bottom:12.0pt'><br>From: Simon Hobson <<a href="mailto:dhcp1@thehobsons.co.uk">dhcp1@thehobsons.co.uk</a>><br>Subject: Re: DHCP Relay: Duplicate packets for DHCPRELEASE and DHCPREQUEST<br>To: "Users of ISC DHCP" <<a href="mailto:dhcp-users@lists.isc.org">dhcp-users@lists.isc.org</a>><br>Date: Wednesday, April 18, 2012, 2:38 PM<o:p></o:p></p><div><p class=MsoNormal>Sujata Verma wrote:<br><br>> I am using dhcp-4.2.2rc1. I have started the dhcp relay with options<br>> <br>> dhcrelay -d -i eth0 -i eth1 serverip<br>> <br>> everything is working fine except that when client release the ip and send DHCPRELEASE packet on server side i get 3 packets for each DHCPRELEASE.<br>> <br>> One is directly sent to server ( which is valid packet) the other two are duplicate of this packet which is generated by relay agent with giaddr as address of eth0 and eth1 interface.<br>> <br>> Is this normal behavior? The same is observed with unicast DHCPREQUEST .<br><br>Are you sure about the unicast packets ? On a switched network, the packet should only ever bee seen by the server - it shouldn't reach the relay agent.<br><br>For any boradcast packets, I'd expect to see two copies - one picked up directly by the server, and one picked up by the relay agent. This is inherent in the way the relay agent needs (due to the way it's built) to listen on both interfaces. I wouldn't expect to see a packet with the relay's eth1 address in it - they aren't connected to the same network are they ?<br><br>-- Simon Hobson<br><br>Visit <a href="http://www.magpiesnestpublishing.co.uk/" target="_blank">http://www.magpiesnestpublishing.co.uk/</a> for books by acclaimed<br>author Gladys Hobson. Novels - poetry - short stories - ideal as<br>Christmas stocking fillers. Some available as e-books.<br>_______________________________________________<br>dhcp-users mailing list<br><a href="/mc/compose?to=dhcp-users@lists.isc.org">dhcp-users@lists.isc.org</a><br><a href="https://lists.isc.org/mailman/listinfo/dhcp-users" target="_blank">https://lists.isc.org/mailman/listinfo/dhcp-users</a><o:p></o:p></p></div></td></tr></table><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Calibri","sans-serif"'><o:p> </o:p></span></p></div></body></html>
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