[Dnsmasq-discuss] No space left in packet

[Carlos Carvalho]

Hans-Joachim Baader (Hans-Joachim.Baader at cjt.de) wrote on 27 May 2008 11:44:
 >I'm currently testing replacing ISC dhdpc with dnsmasq. On one of the test
 >machines I got an error "cannot send DHCP/BOOTP option 43: no space left
 >in packet". This message repeated endlessly and none of the clients could
 >get a lease. All other servers worked fine so far. The other servers have
 >identical configuration, but the clients may have a different PXE BIOS.
 >
 >What could be the cause of this? Following is the complete config file.
 >No command line options are used.

Your client uses bootp, sometimes there's very little space for
options in the packet. You can try removing everything non-essential,
such as net2 options when they're not used.

You may have to build a config tuned for each machine. For example, a
computer here uses dhcp when it boots windows, and there's no space
shortage; in this case it also needs routing info. When it does remote
booting it uses bootp, there's very little space, and it doesn't need
routing. My dhcp-options file has more than 1000 lines... It's
generated by a script.

 >==================================
 >pid-file=/var/run/dnsmasq/dnsmasq.pid
 >no-poll
 >dhcp-no-override
 >domain=domain.local
 >
 >dhcp-range=net1,172.16.73.1,172.16.73.254,1d
 >dhcp-range=net2,192.168.1.101,192.168.1.120,1d
 >
 >dhcp-option=46,1           # netbios node type
 >#dhcp-option=47             # empty netbios scope
 >dhcp-option=net1,option:router,172.16.11.254
 >dhcp-option=net2,option:router,192.168.1.1
 >dhcp-option=6,172.16.1.1
 >dhcp-option=net1,1,255.255.0.0
 >dhcp-option=net2,1,255.255.255.0
 >
 >dhcp-option=43,09:0f:00:03:0c:4e:65:74:77:6f:72:6b:20:62:6f:6f:74:0a:05:00:4d
 >:45:4e:55:06:01:02:08:03:00:03:00:47:04:00:03:00:00:43:01:41:ff
 >
 >dhcp-boot=dummy.0,server043,172.16.1.53
 >bootp-dynamic
 >
 >dhcp-lease-max=254
 >#dhcp-leasefile=/var/lib/misc/dnsmasq.leases
 >dhcp-authoritative
 >==================================
 >
 >The network net2 is not used, there is no second network card in these
 >servers.
 >Option 43 is needed to boot some old PXE clients without a special PXE or
 >mtftp
 >server. Is there something wrong with the config file?