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</o:shapelayout></xml><![endif]--></head><body lang=EN-AU link=blue vlink=purple><div class=WordSection1><p class=MsoNormal>I have dhcp server to use option 82 fields from procurve switches to assign IP addresses based on switch port. This works fine, however there are multiple switches in the same VLAN which are all relaying to the same DHCP server. The dhcp server receives dhcp request from the switch device attaches to, but also from the second switch with trunk port in circuit.id<o:p></o:p></p><p class=MsoNormal>The exchange goes like this for device connected to switch 1:<o:p></o:p></p><p class=MsoListParagraph style='text-indent:-18.0pt;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='mso-list:Ignore'>1.<span style='font:7.0pt "Times New Roman"'> </span></span><![endif]>DHCPDISCOVER via switch 1<o:p></o:p></p><p class=MsoListParagraph style='text-indent:-18.0pt;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='mso-list:Ignore'>2.<span style='font:7.0pt "Times New Roman"'> </span></span><![endif]>DHCPOFFER via switch 1<o:p></o:p></p><p class=MsoListParagraph style='text-indent:-18.0pt;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='mso-list:Ignore'>3.<span style='font:7.0pt "Times New Roman"'> </span></span><![endif]>DHCPDISCOVER via switch 2 (same transaction, circuit.id is trunk port) No free leases <o:p></o:p></p><p class=MsoListParagraph style='text-indent:-18.0pt;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='mso-list:Ignore'>4.<span style='font:7.0pt "Times New Roman"'> </span></span><![endif]>DHCPREQUEST via switch 1<o:p></o:p></p><p class=MsoListParagraph style='text-indent:-18.0pt;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='mso-list:Ignore'>5.<span style='font:7.0pt "Times New Roman"'> </span></span><![endif]>DHCPACK via switch 1<o:p></o:p></p><p class=MsoListParagraph style='text-indent:-18.0pt;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='mso-list:Ignore'>6.<span style='font:7.0pt "Times New Roman"'> </span></span><![endif]>DHCPREQUEST via switch 2 (repeat of step 4)<o:p></o:p></p><p class=MsoListParagraph style='text-indent:-18.0pt;mso-list:l0 level1 lfo1'><![if !supportLists]><span style='mso-list:Ignore'>7.<span style='font:7.0pt "Times New Roman"'> </span></span><![endif]>DHCPNAK via switch 2 because the lease is not associated with this switch as agent.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Depending on the device the NAK will cause it to begin a new DISCOVER and network will never stabilise.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I need to stop the NAK. From the procurve switches the dhcp relay is set per vlan so as far as I can see I can’t prevent them from forwarding requests received on the trunk ports.<o:p></o:p></p><p class=MsoNormal>I’m at a loss as to how to get around this short of running a separate DHCP server per switch.<o:p></o:p></p></div></body></html>