[Dnsmasq-discuss] 54:server-identifier set to '0.0.0.0' in 2.55

[Simon Kelley]

Mike Ruiz wrote:

> 
> Any possibility this is an effect of the goofy network I am in? Or some corruption from the relay?
> 

I think that's not a bad insight. Is this effect intermittent?

My guess is that the following sequence causes it:

1) Client on remote network gets new lease (DHCP interaction goes via relay)

2) dnsmasq is restarted

3) No new leases are given on the network, so no packets come via the relay

4) The client in step one _renews_ the lease, which will go direct, and
not via the relay.

In those circumstances, I can see how a cruicial bit of data might not
be intialised.


A good test would be to find a malfunctioning client and force it to
release and then re-aquire a lease. If that works OK we're on the right
lines.


The main argument I can see against this theory is that it would be
amazing that it has not been found up 'till now.

Simon.

> Here is the dhcpdump of a sample request (not the same as the above):
> 
> ---------------------------------------------------------------------------
>   TIME: 16:53:48.651085
>     IP: > (00:01:e8:76:31:4a) >  (00:21:9b:a6:6e:24)
>     OP: 1 (BOOTPREQUEST)
>  HTYPE: 1 (Ethernet)
>   HLEN: 6
>   HOPS: 1
>    XID: 907bce3f
>   SECS: 65535
>  FLAGS: 0
> CIADDR: 10.32.165.147
> YIADDR: 0.0.0.0
> SIADDR: 0.0.0.0
> GIADDR: 0.0.0.0
> CHADDR: f0:4d:a2:01:62:9f:00:00:00:00:00:00:00:00:00:00
>  SNAME: .
>  FNAME: .
> OPTION:  53 (  1) DHCP message type         3 (DHCPREQUEST)
> OPTION:  55 ( 10) Parameter Request List      1 (Subnet mask)
> 					     28 (Broadcast address)
> 					      2 (Time offset)
> 					      3 (Routers)
> 					     15 (Domainname)
> 					      6 (DNS server)
> 					     12 (Host name)
> 					     40 (NIS domain)
> 					     41 (NIS servers)
> 					     42 (NTP servers)
> 					    
> ---------------------------------------------------------------------------
>   TIME: 16:53:48.686584
>     IP: > (00:21:9b:a6:6e:24) >  (00:00:5e:00:01:29)
>     OP: 2 (BOOTPREPLY)
>  HTYPE: 1 (Ethernet)
>   HLEN: 6
>   HOPS: 1
>    XID: 907bce3f
>   SECS: 65535
>  FLAGS: 0
> CIADDR: 10.32.165.147
> YIADDR: 10.32.165.147
> SIADDR: 172.20.1.116
> GIADDR: 0.0.0.0
> CHADDR: f0:4d:a2:01:62:9f:00:00:00:00:00:00:00:00:00:00
>  SNAME: ks.sec.zynga.com.
>  FNAME: discovery/pxelinux.0.
> OPTION:  53 (  1) DHCP message type         5 (DHCPACK)
> OPTION:  54 (  4) Server identifier         0.0.0.0
> OPTION:  51 (  4) IP address leasetime      259200 (3d)
> OPTION:  58 (  4) T1                        129466 (1d11h57m46s)
> OPTION:  59 (  4) T2                        226666 (2d14h57m46s)
> OPTION:   1 (  4) Subnet mask               255.255.255.128
> OPTION:  12 ( 15) Host name                 netboot-GDNVKN1
> OPTION:   3 (  4) Routers                   10.32.165.129
> OPTION:  42 (  8) NTP servers               172.20.1.116,172.20.1.124
> OPTION:   6 (  8) DNS server                172.20.1.117,172.20.1.125
> OPTION:  15 ( 13) Domainname                sec.zynga.com
> ---------------------------------------------------------------------------
>   TIME: 16:53:48.712433
>     IP: > (00:21:9b:a6:6e:24) >  (00:00:5e:00:01:29)
>     OP: 2 (BOOTPREPLY)
>  HTYPE: 1 (Ethernet)
>   HLEN: 6
>   HOPS: 1
>    XID: 907bce3f
>   SECS: 65535
>  FLAGS: 0
> CIADDR: 10.32.165.147
> YIADDR: 10.32.165.147
> SIADDR: 172.20.1.116
> GIADDR: 0.0.0.0
> CHADDR: f0:4d:a2:01:62:9f:00:00:00:00:00:00:00:00:00:00
>  SNAME: ks.sec.zynga.com.
>  FNAME: discovery/pxelinux.0.
> OPTION:  53 (  1) DHCP message type         5 (DHCPACK)
> OPTION:  54 (  4) Server identifier         0.0.0.0
> OPTION:  51 (  4) IP address leasetime      259200 (3d)
> OPTION:  58 (  4) T1                        118365 (1d8h52m45s)
> OPTION:  59 (  4) T2                        215565 (2d11h52m45s)
> OPTION:   1 (  4) Subnet mask               255.255.255.128
> OPTION:  12 ( 15) Host name                 netboot-GDNVKN1
> OPTION:   3 (  4) Routers                   10.32.165.129
> OPTION:  42 (  8) NTP servers               172.20.1.116,172.20.1.124
> OPTION:   6 (  8) DNS server                172.20.1.117,172.20.1.125
> OPTION:  15 ( 13) Domainname                sec.zynga.com
> ---------------------------------------------------------------------------
> 
> 
> -Mike
> 
>>> I should mention at this point that the configuration has grown rather large:
>>>
>>> [root at netops-adm-1 ~]# egrep -v '^#|^$' /etc/dnsmasq.conf | wc
>>>  12515   12530 1013088
>>> [root at netops-adm-1 ~]# grep dhcp-host /etc/dnsmasq.conf | wc
>>>   5735    5951  514853
>>>
>> Nice to see that it keeps going at those sizes: there shouldn't be any
>> problems just because of the size of the config.
>>
>>
>> Simon.
>>
>>
>>> -Mike
> 
>