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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='color:#1F497D'>I see no reason why that wouldn’t work. On boot the phone should issue a DHCP broadcast which will go to the ip helper address, from there it should dish out addresses in a range based on the ip of the default gateway of that subnet.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>The only problem I’ve ever seen is when the DHCP server/TFTP server IP address is hard-coded into the phone itself. From that I had to do the 123456789*0# reset on the phone to get it to forget.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Anyone else have a different experience?<o:p></o:p></span></p><p class=MsoNormal><span style='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"'> cisco-voip-bounces@puck.nether.net [mailto:cisco-voip-bounces@puck.nether.net] <b>On Behalf Of </b>Tim Reimers<br><b>Sent:</b> Wednesday, February 01, 2012 4:31 PM<br><b>To:</b> cisco-voip@puck.nether.net<br><b>Subject:</b> [cisco-voip] IP phone DHCP question or two<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Hi all –<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>What are all the options for forcing an IP phone to get a new IP address?<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I know of:<o:p></o:p></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo2'><![if !supportLists]><span style='mso-list:Ignore'>-<span style='font:7.0pt "Times New Roman"'> </span></span><![endif]>Resetting it (I think) (how does one globally reset all phones in UCM?)<o:p></o:p></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo2'><![if !supportLists]><span style='mso-list:Ignore'>-<span style='font:7.0pt "Times New Roman"'> </span></span><![endif]>shut/no shut the port<o:p></o:p></p><p class=MsoListParagraph style='text-indent:-.25in;mso-list:l0 level1 lfo2'><![if !supportLists]><span style='mso-list:Ignore'>-<span style='font:7.0pt "Times New Roman"'> </span></span><![endif]>int range (whatever to whatever) and inline power never/inline power auto <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I want to switch from Cisco router based DHCP to Microsoft DHCP<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>My plan would be:<o:p></o:p></p><p class=MsoNormal>Disable the ip dhcp pool on the cisco router for a given Vlan/subnet<o:p></o:p></p><p class=MsoNormal>Enable the ip helper addresses<o:p></o:p></p><p class=MsoNormal>Restart the phones and they would pull IP addresses from the new DHCP server.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I know Microsoft devices (aka XP, win7 workstations) tend to know their old IP and will sometimes cause an IP conflict when changing DHCP servers, <o:p></o:p></p><p class=MsoNormal>even if you reboot them they sometimes conflict.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Do Cisco IP phones have that same problem, or once they reset do they forget all about any IP they once had, and go get a new one from the DHCP server<o:p></o:p></p><p class=MsoNormal>(obviously, if the DHCP server has a lease for the phone, it gets the same IP back, but that’s not the phone’s doing..)<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>thanks, Tim<o:p></o:p></p></div></body></html>