[Dnsmasq-discuss] dnsmasq ignoring some clients

Chris Marget chris at logsoft.com
Thu Oct 2 18:14:10 BST 2008


On Thu, 2 Oct 2008, Simon Kelley wrote:
> Chris Marget wrote:
> 
> >     Option: (t=50,l=4) Requested IP Address = 255.255.255.255
> >         Option: (50) Requested IP Address
> >         Length: 4
> >         Value: FFFFFFFF
>                   ^^^^^^^^
> The client is asking for IP address 255.255.255.255, that doesn't look 
> right at all. A server identifier of 1.2.3.4 looks suspicious too, is 
> that the IP address of you DHCP server?

Hi Simon.  Thank you for your attention.

Here's the scoop.  the client is a disk image of a pre-installed linux
system.  I got it here:  http://jailtime.org/download:centos:v5.2

It's a pre-built "drop into your xvm engine" kind of thing, and comes
with the baggage of the environment of the guy who built it.

So, yes, the client is very confused about his environment.

I agree that asking for 255.255.255.255 is somewhat strange, but
shouldn't dnsmasq NAK this request just like any other transplanted
client?

My other DHCP server (ISC - running on a different box) serves this
client just fine.  The authoritative statement is required, of course.
Here's the transaction according to the ISC server's debug output:

DHCPREQUEST for 255.255.255.255 (1.2.3.4) from 00:16:3e:11:11:11 via nge0: wrong network.
DHCPNAK on 255.255.255.255 to 00:16:3e:11:11:11 via nge0
DHCPDISCOVER from 00:16:3e:11:11:11 via nge0
DHCPOFFER on 192.168.1.81 to 00:16:3e:11:11:11 via nge0
DHCPREQUEST for 192.168.1.81 (192.168.1.8) from 00:16:3e:11:11:11 via nge0
DHCPACK on 192.168.1.81 to 00:16:3e:11:11:11 via nge0

...and now the (rather lengthy) dump of the 6 packets associated with
the 6 lines of debug output.  I've trimmed the lower layer protocol
details in an attempt at brevity.

Thanks!

/chris


DHCPREQUEST for 255.255.255.255 (1.2.3.4) from 00:16:3e:11:11:11 via
nge0: wrong network.
Bootstrap Protocol
    Message type: Boot Request (1)
    Hardware type: Ethernet
    Hardware address length: 6
    Hops: 0
    Transaction ID: 0xdcbfd683
    Seconds elapsed: 0
    Bootp flags: 0x0000 (Unicast)
        0... .... .... .... = Broadcast flag: Unicast
        .000 0000 0000 0000 = Reserved flags: 0x0000
    Client IP address: 0.0.0.0 (0.0.0.0)
    Your (client) IP address: 255.255.255.255 (255.255.255.255)
    Next server IP address: 255.255.255.255 (255.255.255.255)
    Relay agent IP address: 0.0.0.0 (0.0.0.0)
    Client MAC address: Xensourc_11:11:11 (00:16:3e:11:11:11)
    Server host name not given
    Boot file name not given
    Magic cookie: (OK)
    Option: (t=53,l=1) DHCP Message Type = DHCP Request
        Option: (53) DHCP Message Type
        Length: 1
        Value: 03
    Option: (t=54,l=4) Server Identifier = 1.2.3.4
        Option: (54) Server Identifier
        Length: 4
        Value: 01020304
    Option: (t=50,l=4) Requested IP Address = 255.255.255.255
        Option: (50) Requested IP Address
        Length: 4
        Value: FFFFFFFF
    Option: (t=55,l=7) Parameter Request List
        Option: (55) Parameter Request List
        Length: 7
        Value: 0103060C0F1128
        1 = Subnet Mask
        3 = Router
        6 = Domain Name Server
        12 = Host Name
        15 = Domain Name
        17 = Root Path
        40 = Network Information Service Domain
    End Option
    Padding

DHCPNAK on 255.255.255.255 to 00:16:3e:11:11:11 via nge0
Bootstrap Protocol
    Message type: Boot Reply (2)
    Hardware type: Ethernet
    Hardware address length: 6
    Hops: 0
    Transaction ID: 0xdcbfd683
    Seconds elapsed: 0
    Bootp flags: 0x8000 (Broadcast)
        1... .... .... .... = Broadcast flag: Broadcast
        .000 0000 0000 0000 = Reserved flags: 0x0000
    Client IP address: 0.0.0.0 (0.0.0.0)
    Your (client) IP address: 0.0.0.0 (0.0.0.0)
    Next server IP address: 192.168.1.8 (192.168.1.8)
    Relay agent IP address: 0.0.0.0 (0.0.0.0)
    Client MAC address: Xensourc_11:11:11 (00:16:3e:11:11:11)
    Server host name not given
    Boot file name not given
    Magic cookie: (OK)
    Option: (t=53,l=1) DHCP Message Type = DHCP NAK
        Option: (53) DHCP Message Type
        Length: 1
        Value: 06
    Option: (t=54,l=4) Server Identifier = 192.168.1.8
        Option: (54) Server Identifier
        Length: 4
        Value: C0A80108
    End Option
    Padding

DHCPDISCOVER from 00:16:3e:11:11:11 via nge0
Bootstrap Protocol
    Message type: Boot Request (1)
    Hardware type: Ethernet
    Hardware address length: 6
    Hops: 0
    Transaction ID: 0xdcbfd683
    Seconds elapsed: 2
    Bootp flags: 0x0000 (Unicast)
        0... .... .... .... = Broadcast flag: Unicast
        .000 0000 0000 0000 = Reserved flags: 0x0000
    Client IP address: 0.0.0.0 (0.0.0.0)
    Your (client) IP address: 255.255.255.255 (255.255.255.255)
    Next server IP address: 255.255.255.255 (255.255.255.255)
    Relay agent IP address: 0.0.0.0 (0.0.0.0)
    Client MAC address: Xensourc_11:11:11 (00:16:3e:11:11:11)
    Server host name not given
    Boot file name not given
    Magic cookie: (OK)
    Option: (t=53,l=1) DHCP Message Type = DHCP Discover
        Option: (53) DHCP Message Type
        Length: 1
        Value: 01
    Option: (t=55,l=7) Parameter Request List
        Option: (55) Parameter Request List
        Length: 7
        Value: 0103060C0F1128
        1 = Subnet Mask
        3 = Router
        6 = Domain Name Server
        12 = Host Name
        15 = Domain Name
        17 = Root Path
        40 = Network Information Service Domain
    End Option
    Padding

DHCPOFFER on 192.168.1.81 to 00:16:3e:11:11:11 via nge0
Bootstrap Protocol
    Message type: Boot Reply (2)
    Hardware type: Ethernet
    Hardware address length: 6
    Hops: 0
    Transaction ID: 0xdcbfd683
    Seconds elapsed: 2
    Bootp flags: 0x0000 (Unicast)
        0... .... .... .... = Broadcast flag: Unicast
        .000 0000 0000 0000 = Reserved flags: 0x0000
    Client IP address: 0.0.0.0 (0.0.0.0)
    Your (client) IP address: 192.168.1.81 (192.168.1.81)
    Next server IP address: 192.168.1.1 (192.168.1.1)
    Relay agent IP address: 0.0.0.0 (0.0.0.0)
    Client MAC address: Xensourc_11:11:11 (00:16:3e:11:11:11)
    Server host name not given
    Boot file name not given
    Magic cookie: (OK)
    Option: (t=53,l=1) DHCP Message Type = DHCP Offer
        Option: (53) DHCP Message Type
        Length: 1
        Value: 02
    Option: (t=54,l=4) Server Identifier = 192.168.1.1
        Option: (54) Server Identifier
        Length: 4
        Value: C0A80101
    Option: (t=51,l=4) IP Address Lease Time = 16 hours, 14 minutes, 56
seconds
        Option: (51) IP Address Lease Time
        Length: 4
        Value: 0000E480
    Option: (t=58,l=4) Renewal Time Value = 8 hours, 7 minutes, 28
seconds
        Option: (58) Renewal Time Value
        Length: 4
        Value: 00007240
    Option: (t=59,l=4) Rebinding Time Value = 14 hours, 13 minutes, 4
seconds
        Option: (59) Rebinding Time Value
        Length: 4
        Value: 0000C7F0
    Option: (t=1,l=4) Subnet Mask = 255.255.255.0
        Option: (1) Subnet Mask
        Length: 4
        Value: FFFFFF00
    Option: (t=15,l=3) Domain Name = "lan"
        Option: (15) Domain Name
        Length: 3
        Value: 6C616E
    Option: (t=6,l=4) Domain Name Server = 192.168.1.1
        Option: (6) Domain Name Server
        Length: 4
        Value: C0A80101
    Option: (t=3,l=4) Router = 192.168.1.1
        Option: (3) Router
        Length: 4
        Value: C0A80101
    End Option
    Padding

DHCPREQUEST for 192.168.1.81 (192.168.1.8) from 00:16:3e:11:11:11 via
nge0
Bootstrap Protocol
    Message type: Boot Request (1)
    Hardware type: Ethernet
    Hardware address length: 6
    Hops: 0
    Transaction ID: 0xdcbfd683
    Seconds elapsed: 2
    Bootp flags: 0x0000 (Unicast)
        0... .... .... .... = Broadcast flag: Unicast
        .000 0000 0000 0000 = Reserved flags: 0x0000
    Client IP address: 0.0.0.0 (0.0.0.0)
    Your (client) IP address: 255.255.255.255 (255.255.255.255)
    Next server IP address: 255.255.255.255 (255.255.255.255)
    Relay agent IP address: 0.0.0.0 (0.0.0.0)
    Client MAC address: Xensourc_11:11:11 (00:16:3e:11:11:11)
    Server host name not given
    Boot file name not given
    Magic cookie: (OK)
    Option: (t=53,l=1) DHCP Message Type = DHCP Request
        Option: (53) DHCP Message Type
        Length: 1
        Value: 03
    Option: (t=54,l=4) Server Identifier = 192.168.1.8
        Option: (54) Server Identifier
        Length: 4
        Value: C0A80108
    Option: (t=50,l=4) Requested IP Address = 192.168.1.81
        Option: (50) Requested IP Address
        Length: 4
        Value: C0A80151
    Option: (t=55,l=7) Parameter Request List
        Option: (55) Parameter Request List
        Length: 7
        Value: 0103060C0F1128
        1 = Subnet Mask
        3 = Router
        6 = Domain Name Server
        12 = Host Name
        15 = Domain Name
        17 = Root Path
        40 = Network Information Service Domain
    End Option
    Padding

DHCPACK on 192.168.1.81 to 00:16:3e:11:11:11 via nge0
Bootstrap Protocol
    Message type: Boot Reply (2)
    Hardware type: Ethernet
    Hardware address length: 6
    Hops: 0
    Transaction ID: 0xdcbfd683
    Seconds elapsed: 2
    Bootp flags: 0x0000 (Unicast)
        0... .... .... .... = Broadcast flag: Unicast
        .000 0000 0000 0000 = Reserved flags: 0x0000
    Client IP address: 0.0.0.0 (0.0.0.0)
    Your (client) IP address: 192.168.1.81 (192.168.1.81)
    Next server IP address: 0.0.0.0 (0.0.0.0)
    Relay agent IP address: 0.0.0.0 (0.0.0.0)
    Client MAC address: Xensourc_11:11:11 (00:16:3e:11:11:11)
    Server host name not given
    Boot file name not given
    Magic cookie: (OK)
    Option: (t=53,l=1) DHCP Message Type = DHCP ACK
        Option: (53) DHCP Message Type
        Length: 1
        Value: 05
    Option: (t=54,l=4) Server Identifier = 192.168.1.8
        Option: (54) Server Identifier
        Length: 4
        Value: C0A80108
    Option: (t=51,l=4) IP Address Lease Time = 12 hours
        Option: (51) IP Address Lease Time
        Length: 4
        Value: 0000A8C0
    Option: (t=1,l=4) Subnet Mask = 255.255.255.0
        Option: (1) Subnet Mask
        Length: 4
        Value: FFFFFF00
    Option: (t=3,l=4) Router = 192.168.1.1
        Option: (3) Router
        Length: 4
        Value: C0A80101
    Option: (t=6,l=8) Domain Name Server
        Option: (6) Domain Name Server
        Length: 8
        Value: C0A8010104020201
        IP Address: 192.168.1.1
        IP Address: 4.2.2.1
    End Option
    Padding




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