[BackupPC-users] xxx is a DHCP host, and I don't know its IP address...

[itismike <bac...@ba...>]

I emailed this to the bac...@li... address last night but didn't see it go out. My apologies if this is the second time you're seeing it.

-Mike


I've been struggling with this error for too long and need to ask for some help. I had BackupPC working when my IP address was set as a pre-defined lease in my router. But I decided to instead configure the laptop as a DHCP client so I could back up over Ethernet or wireless. This is the error I now get in the CGI when attempting to perform a backup:
---
"Error: Can't find IP address for michael-ubuntu
michael-ubuntu is a DHCP host, and I don't know its IP address. I checked the netbios name of 192.168.1.117, and found that that machine is not michael-ubuntu. Until I see michael-ubuntu at a particular DHCP address, you can only start this request from the client machine itself."
---

As others have reported, the IP address is actually correct for my client. Originally I thought it was a DNS issue, and I chased down a bug in Ubuntu that doesn't broadcast it's hostname during a DHCP request. Adding the following to my /etc/dhcp3/dhclient.conf file resolved that:

send fqdn.server-update on


That, in conjunction with running DNSMasq on the router allows me to ping the target laptop via hostname from the BackupPC server, which wasn't working prior to this change. However this solved nothing for BackupPC as it still returning the error above.

Several google searches landed me mostly in the archives of the BackupPC mailing list, and steered me toward the "NmbLookupFindHostCmd" setting within config.pl. One post suggested modifying settings for NmbLookupFindHostCmd, but I'd rather try to stick with standard settings than break things that are there for a reason. Plus, this was all working fine until I decided to disable assigned IP addresses in my DHCP settings, so I believe it has the ability to connect without disabling/modifying this check.

I learned that nmblookup -A <IP_address> is supposed to return a hostname, and it does not.

To test things, I ran BackupPC_dump as the backuppc user on my server, but I don't think it tells me anything about this nmblookup situation (although I am surprised that it claims that the ping response is to slow):

====
$ /usr/share/backuppc/bin/BackupPC_dump -v -f michael-ubuntu
cmdSystemOrEval: about to system /bin/ping -c 1 michael-ubuntu
cmdSystemOrEval: finished: got output PING michael-ubuntu.mikeshome
(192.168.1.117) 56(84) bytes of data.
64 bytes from michael-Ubuntu.mikeshome (192.168.1.117): icmp_seq=1
ttl=64 time=16.5 ms

--- michael-ubuntu.mikeshome ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms rtt min/avg/max/mdev = 16.507/16.507/16.507/0.000 ms

cmdSystemOrEval: about to system /bin/ping -c 1 michael-ubuntu
cmdSystemOrEval: finished: got output PING michael-ubuntu.mikeshome (192.168.1.117) 56(84) bytes of data.
64 bytes from michael-Ubuntu.mikeshome (192.168.1.117): icmp_seq=1 ttl=64 time=97.5 ms

--- michael-ubuntu.mikeshome ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms rtt min/avg/max/mdev = 97.563/97.563/97.563/0.000 ms

CheckHostAlive: returning 97.563
ping too slow: 97.56msec (threshold is 20msec)
$
====

I'm not sure where to go from here. How can I test this nmblookup deal?

Thanks,
Mike

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