Multiple subnets across different vlans

Glenn Satchell glenn.satchell at uniq.com.au
Sat Jul 9 08:01:14 UTC 2011


On 07/09/11 17:45, Joshua Beard wrote:
> Thanks for the responses.  I've had 'authoritative' set since deploying the server.  As far as the shared-network, I didn't have that configured for very long.
>
>> From the looks of it, it's limited to a handful of clients that are giving the 'wrong network' error, and they're all on the same subnet.  In fact, the logs are pretty full of a handful of clients continuously making requests.  For example:
> Jul  9 01:39:17 ns1 dhcpd: DHCPREQUEST for 172.30.99.41 (172.30.112.121) from 00:50:41:72:67:2e via eth0: wrong network.
> Jul  9 01:39:17 ns1 dhcpd: DHCPNAK on 172.30.99.41 to 00:50:41:72:67:2e via eth0
> Jul  9 01:39:17 ns1 dhcpd: DHCPREQUEST for 172.30.99.24 (172.30.112.121) from 00:50:41:72:63:be via eth0: wrong network.
> Jul  9 01:39:17 ns1 dhcpd: DHCPNAK on 172.30.99.24 to 00:50:41:72:63:be via eth0
> Jul  9 01:39:18 ns1 dhcpd: DHCPREQUEST for 172.30.99.10 (172.30.112.121) from 00:50:41:72:65:19 via eth0: wrong network.
> Jul  9 01:39:18 ns1 dhcpd: DHCPNAK on 172.30.99.10 to 00:50:41:72:65:19 via eth0
> Jul  9 01:39:19 ns1 dhcpd: DHCPREQUEST for 172.30.99.62 (172.30.112.121) from 00:50:41:72:5d:01 via eth0: wrong network.
> Jul  9 01:39:19 ns1 dhcpd: DHCPNAK on 172.30.99.62 to 00:50:41:72:5d:01 via eth0
> Jul  9 01:39:21 ns1 dhcpd: DHCPREQUEST for 172.30.99.41 (172.30.112.121) from 00:50:41:72:67:2e via eth0: wrong network.
> Jul  9 01:39:21 ns1 dhcpd: DHCPNAK on 172.30.99.41 to 00:50:41:72:67:2e via eth0
> Jul  9 01:39:21 ns1 dhcpd: DHCPREQUEST for 172.30.99.24 (172.30.112.121) from 00:50:41:72:63:be via eth0: wrong network.
>
> I don't know the state of those current machines, but I would've assumed they were sleeping.  Could some sort of wake-on-lan feature be continuously making requests?
>
>>> Is 172.30.112.121 the address of the DHCP server?
>
> Yes, this is the DHCP server.
>
> Another question, if I may ask without starting a new topic, and I think I already know the answer.  Along with DHCP, I migrated DNS from a Windows server to a Linux box running BIND.  I did a zone transfer for this migration.  Things seem mostly happy, but a lot of clients produce this in the dhcpd logs:
>
> Jul  9 01:38:06 ns1 dhcpd: Forward map from MS40102S44572.dsdk12.schoollocal. to 172.30.133.41 FAILED: Has an A record but no DHCID, not mine.
>
> Obviously, they were leased with the old dhcp server and their A records were migrated in the zone transfer.  I'm using dynamic dns updates here, and from what I've seen, these clients fail to get an address if there's already a DNS record for them.  FWIW, this is a k-12 school district and most everyone's gone for the summer, so if I have to, I can just remove all of the DNS records for the dynamic hosts.  Any suggestions here?
>
> As far as the 'wrong network' goes, it sounds like I need to just wait it out to clean itself up.
>
> Thanks,
> Josh
>

In addition to A and PTR records, dhcpd adds a TXT record containing a 
magic DHCID value. If this TXT exists with the right value then dhcpd 
knows that it created the corresponding A record, so it can delete it 
later if required.

in your case the simplest fix would be to remove all the dynamic ip 
records from the zone file. When dhcpd allocates or updates a lease it 
will send a request to create the new records and everything will be 
happy :)

regards,
-glenn



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