----- Forwarded message from RLW <[email protected]> ----- From: RLW <[email protected]> Date: Thu, 28 Jun 2018 10:51:02 +0200 To: Stuart Henderson <[email protected]> Reply-To: [email protected] User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 Subject: DHCPD and RFC 6842 - printer problems
Hi Stuart, I don't know how to reply to old posts, so I am writing to you. There is a problem with DHCPD and RFC 6842, 6.0 -> 6.1 change. Printers like Xerox, OKI don't get IP from dhcpd unless you set this option: echo-client-id false; Printers send dhcp discover, get dhcp offer, but don't send dhcp request. It was first announced here: https://marc.info/?l=openbsd-misc&m=149252692825528&w=2 It took me 2 days of checking different setups and looking for answers on the Internet. Then I wrote to the post author and he wrote me back with the solution. Maybe information about this problem should be added to dhcpd.conf manual?? best regards, RLW ----- End forwarded message ----- Obviously hitting the "It is possible, though unlikely, that clients will drop packets that contain this formerly unexpected option" mentioned in the RFC. OK to add this to the manual? (Large context to show that "false or off" is similarly worded to "true or on" earlier). Index: dhcpd.conf.5 =================================================================== RCS file: /cvs/src/usr.sbin/dhcpd/dhcpd.conf.5,v retrieving revision 1.23 diff -u -p -u -8 -r1.23 dhcpd.conf.5 --- dhcpd.conf.5 1 Mar 2018 20:48:11 -0000 1.23 +++ dhcpd.conf.5 28 Jun 2018 09:34:37 -0000 @@ -868,16 +868,18 @@ statement enables or disables RFC 6842 c .Pp If it is present and has a value of true or on, and a DHCP DISCOVER or REQUEST is received which contains the client identifier option (Option code 61), the server will copy the option into its response (DHCP ACK or NAK) per RFC 6842. In other words if the client sends the option it will receive it back. By default, this flag is on and client identifiers will be echoed back to the client. +Some devices, especially old printers, might not accept an offer from +the server unless this is set to false or off. .Sh REFERENCE: OPTION STATEMENTS DHCP option statements are documented in the .Xr dhcp-options 5 manual page. .Sh SEE ALSO .Xr dhcp-options 5 , .Xr dhcpd.leases 5 , .Xr dhcpd 8
