[Dnsmasq-discuss] Re: Re: DCHP server not assign IP addresses
troy at piggo.com
Tue Nov 18 06:09:30 GMT 2008
* Rune Kock wrote :
>* Troy Piggins wrote:
>> * Rune Kock wrote :
>>>* Troy Piggins wrote:
>>>> My dnsmasq 2.41 doesn't seem to be assigning DHCP IP addresses.
>>>> Been running the server for some time, but mainly for the DNS
>>>> side of things. The IP addresses for most machines on my network
>>>> are static, so hasn't been a problem. But I'm trying to connect
>>>> to a NAS (WD My Book World Edition) which I believe needs a DHCP
>>>> server to get an IP address, and I can't interface with it to set
>>>> it up without one.
>>> 2) Check your firewall settings. The following is from dnsmasq's FAQ:
>>> The first thing to check is the broadcast address set for the
>>> ethernet interface. This is normally the adddress on the connected
>>> network with all ones in the host part. For instance if the
>>> address of the ethernet interface is 192.168.55.7 and the netmask
>>> is 255.255.255.0 then the broadcast address should be
>>> 192.168.55.255. Having a broadcast address which is not on the
>>> network to which the interface is connected kills things stone
>> Not sure where this is set in dnsmasq.conf? The only things I
>> have set are shown below. Everything else, I assume, is the
>> default. I searched the excellently commented dnsmasq.conf file
>> for "broadcast", and thought I'd try the "dhcp-authoritative"
>> command to see if that helped. It didn't.
> Well, this part is about the setup of the network interface. Check
> with ifconfig.
Aah, of course. Sorry.
eth1 Link encap:Ethernet HWaddr 00:19:66:40:80:8d
inet addr:192.168.0.1 Bcast:192.168.0.255 Mask:255.255.255.0
>> The only other thing I could find was:
>> # Send options to hosts which ask for a DHCP lease.
>> # See RFC 2132 for details of available options.
>> # Note that all the common settings, such as netmask and
>> # broadcast address, DNS server and default route, are given
>> # sane defaults by dnsmasq. You very likely will not need any
>> # any dhcp-options. If you use Windows clients and Samba, there
>> # are some options which are recommended, they are detailed at
>> # the
>> # end of this section.
>> # For reference, the common options are:
>> # subnet mask - 1
>> # default router - 3
>> # DNS server - 6
>> # broadcast address - 28
>> But couldn't find what the 28 signified. Shed any light?
>This is irrelevant. It's about specifying broadcast to the client.
>>> The second potential problem relates to firewall rules: since the ISC
>>> daemon in some configurations bypasses the kernel firewall rules
>>> entirely, the ability to run the ISC daemon does not indicate
>>> that the current configuration is OK for the dnsmasq daemon.
>>> For the dnsmasq daemon to operate it's vital that UDP packets to
>>> and from ports 67 and 68 and broadcast packets with source
>>> address 0.0.0.0 and destination address 255.255.255.255 are not
>>> dropped by iptables/ipchains.
>> Both ports allow UDP:
>> $ sudo iptables-save | grep 67
>> -A udpincoming_packets -p udp -m udp --sport 67:68 --dport 67:68 -j ACCEPT
> I'm not entirely fluent in iptables syntax, but to me this sounds like
> "accept packets with source port 67/68 AND dest port 67/68".
I see. You're interpretation is correct. I thought the requests
only came and went on those ports.
> I believe that you need "accept source port 67/68 OR dest port
I split the rules up as you suggested.
It still is not assigning addresses.
Troy Piggins | http://piggo.com/~troy
Peter Anspach's Top 100 Thing's I'd Do If I Ever Became An Evil Overlord:
94. When arresting prisoners, my guards will not allow them to stop and grab a
useless trinket of purely sentimental value.
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