<html><head><style type='text/css'>p { margin: 0; }</style></head><body><div style='font-family: Andale Mono; font-size: 10pt; color: #000000'><div style="color: rgb(0, 0, 0); font-family: 'Andale Mono'; font-size: 10pt; ">BTW: we are running isc dhcp 4.2.3p1</div><div style="color: rgb(0, 0, 0); font-family: 'Andale Mono'; font-size: 10pt; "><br></div><font face="'Andale Mono'" size="2">I assume the ia-na .... from the leases file is similar to the UID from DHCPv4 leases file:</font><div style="color: rgb(0, 0, 0); font-family: 'Andale Mono'; font-size: 10pt; "><br></div><div><div><font face="'Andale Mono'" size="2">uid client-identifier;</font></div><div><font face="'Andale Mono'" size="2"><br></font></div><div><font face="'Andale Mono'" size="2"> The uid statement records the client identifier used by the client to acquire the lease. Clients are not required to send client identifiers, and this statement only appears if the client did in fact send one. Client identifiers are normally an</font></div><div><font face="'Andale Mono'" size="2"> ARP type (1 for ethernet) followed by the MAC address, just like in the hardware statement, but this is not required.</font></div><div><font face="'Andale Mono'" size="2"><br></font></div><div><font face="'Andale Mono'" size="2"> The client identifier is recorded as a colon-separated hexadecimal list or as a quoted string. If it is recorded as a quoted string and it contains one or more non-printable characters, those characters are represented as octal escapes - a back-</font></div><div><font face="'Andale Mono'" size="2"> slash character followed by three octal digits.</font></div><br><div style="color: rgb(0, 0, 0); font-family: 'Andale Mono'; font-size: 10pt; "><br></div><hr id="zwchr" style="color: rgb(0, 0, 0); font-family: 'Andale Mono'; font-size: 10pt; "><blockquote style="border-left-width: 2px; border-left-style: solid; border-left-color: rgb(16, 16, 255); margin-left: 5px; padding-left: 5px; color: rgb(0, 0, 0); font-weight: normal; font-style: normal; text-decoration: none; font-family: Helvetica, Arial, sans-serif; font-size: 12pt; "><b>From: </b>"perl-list" <perl-list@network1.net><br><b>To: </b>"Users of ISC DHCP" <dhcp-users@lists.isc.org><br><b>Sent: </b>Wednesday, January 25, 2012 3:35:21 PM<br><b>Subject: </b>Re: DHCPv6 and MAC Address inclusion<br><br><style>p { margin: 0; }</style><div style="font-family: Andale Mono; font-size: 10pt; color: #000000"><font face="'Andale Mono'" size="2">It SEEMS like the windows machine is using the MAC although I am not sure of DUID vs IAID and where each can be seen.</font><div style="color: rgb(0, 0, 0); font-family: 'Andale Mono'; font-size: 10pt; "><br></div><div style="color: rgb(0, 0, 0); font-family: 'Andale Mono'; font-size: 10pt; ">I just disabled / enabled adapter on test windows7 laptop here ... I have some numbers available (sans packet capture) from logs and from the leases file (dhcpd ):</div><div style="color: rgb(0, 0, 0); font-family: 'Andale Mono'; font-size: 10pt; "><br></div><div><font face="'Andale Mono'" size="2"><b>00:15:c5:14:ce:b0</b> (the actual mac of the windows computer)</font></div><div><font face="'Andale Mono'" size="2">dhcpd: Client <u>00:01:00:01:13:e0:fd:f1:<b>00:15:c5:14:ce:b0</b></u> releases address 2620:0:2e50:e8:1::f541 (line from the log file - I assume that is DUID - seems to contain full mac)</font></div><div><font face="'Andale Mono'" size="2">ia-na "\305\025\000\020\000\001\000\001\023\340\375\361\000\025\305\024\316\260" (Opener to the lease entry in leases file - i have no idea what that string of stuff is)</font></div><div><br><div style="color: rgb(0, 0, 0); font-family: 'Andale Mono'; font-size: 10pt; "><br></div><hr id="zwchr" style="color: rgb(0, 0, 0); font-family: 'Andale Mono'; font-size: 10pt; "><blockquote style="border-left-width: 2px; border-left-style: solid; border-left-color: rgb(16, 16, 255); margin-left: 5px; padding-left: 5px; color: rgb(0, 0, 0); font-weight: normal; font-style: normal; text-decoration: none; font-family: Helvetica, Arial, sans-serif; font-size: 12pt; "><b>From: </b>"Michael Dean Pugh" <mdpugh@hotmail.com><br><b>To: </b>dhcp-users@isc.org<br><b>Sent: </b>Wednesday, January 25, 2012 3:00:05 PM<br><b>Subject: </b>Re: DHCPv6 and MAC Address inclusion<br><br>I'm jumping in at the end here and not responding to any particular post. I <br>have followed this thread with great interest. This seems like a good time to <br>make an observation and ask a question.<br><br>There is much talk about deriving the MAC address from IPv6 identifiers. <br>While it's true that in most cases (every case I've personally observed--<br>Windows and FreeBSD) the MAC is part of the DUID, this is only useful if the <br>host has one interface as the DUID is unique to the host not the interface (I <br>think we're all in agreement here). Also, once the host has assigned itself <br>the DUID, the interface can be replaced, but the DUID will remain the same, so <br>the MAC address derived from the DUID at this point would be invalid. Again, <br>this is with Windows and FreeBSD.<br><br>Now, the observation. Microsoft encodes the first 24 bits of the MAC address <br>(the manufacturer portion) in the IAID by directly copying them into the last <br>24 bits of the IAID. In other words, if the MAC is 01:23:45:ab:cd:ef, the <br>IAID is xy012345(Hex) for some x and y. This has limited usefulness since it <br>is entirely possible to have more than one interface from the same <br>manufacturer installed in one host (it seems like it would have made more <br>sense to have used the last 24 bits of the MAC).<br><br>This brings me to the question. Does anyone know how the first 8 bits of the <br>IAID are derived by Microsoft? I'm pretty sure I found this somewhere on the <br>Internet, but have been unable to find it again. I'm also wondering if <br>Microsoft's IAID algorithm is based on any standards or if the IAID is merely <br>a 32-bit number. It does seem that the IAID holds enough information to <br>uniquely identify each interface on a single managed network.<br><br><br><br>_______________________________________________<br>dhcp-users mailing list<br>dhcp-users@lists.isc.org<br>https://lists.isc.org/mailman/listinfo/dhcp-users<br><br></blockquote><br></div></div><br>_______________________________________________<br>dhcp-users mailing list<br>dhcp-users@lists.isc.org<br>https://lists.isc.org/mailman/listinfo/dhcp-users</blockquote><br></div></div></body></html>