dhcpd doesn't acknowledge dhcp requests

[Sean McMurray]

On 06/02/2015 03:40 PM, Graham Clinch wrote:
>> I have a dhcp server that won't give out leases and doesn't acknowledge
>> DHCPDISCOVERs.
>>
>> I see the requests come in with tcpdump, but the daemon doesn't log them
>> and doesn't respond.
>>
>> [snip]
>>
>>   >ss -anlp | grep ':67'
>> tcp    UNCONN     0      0 *:67                    *:*
>> users:(("dhcpd",21614,9))
> Is the daemon listening on interface em2?
>
> # ss -anp | grep dhcpd
> p_raw  UNCONN     0      0                      *:eth0                   *      users:(("dhcpd",24985,5))
> [...]
>
> Alternatively, running the daemon manually in debug mode (-d) should give some hints as to the interfaces it's discovered:
>
> Listening on LPF/eth0/00:14:22:28:ad:83/192.168.125.0/24
> Sending on   LPF/eth0/00:14:22:28:ad:83/192.168.125.0/24
> Sending on   Socket/fallback/fallback-net
On startup it says that it is Listening and Sending on em2. It also 
lists interfaces it will ignore because there is no matching subnet 
declared in dhcpd.conf.

It also says:

	Sending on   Socket/fallback/fallback-net

> ss -anp | grep dhcpd
p_raw  UNCONN     0      0                      *:em2                  *      users:(("dhcpd",21614,5))
u_str  ESTAB      0      0                      * 558943                 * 559749 users:(("dhcpd",21614,2),("dhcpd",21614,1))
u_dgr  UNCONN     0      0                      * 558954                 * 8044  users:(("dhcpd",21614,3))
raw    UNCONN     0      0                      *:1                     *:*      users:(("dhcpd",21614,4))
tcp    UNCONN     0      0                      *:14659                 *:*      users:(("dhcpd",21614,20))
tcp    UNCONN     0      0                      *:67                    *:*      users:(("dhcpd",21614,9))
tcp    UNCONN     0      0                     :::23465                :::*      users:(("dhcpd",21614,21))
tcp    LISTEN     0      1            10.64.0.104:647                   *:*      users:(("dhcpd",21614,11))
tcp    ESTAB      0      0            10.64.0.104:647         10.64.0.112:56061  users:(("dhcpd",21614,10))