IP Address Problems

Roger Haxton rhaxton at swbell.net
Wed Jan 11 17:21:28 UTC 2006

On Wednesday 11 January 2006 10:47, Michael J. Lynch wrote:
> I don't think it's a dhcpcd vs. dhclient3 issue.  I'm using both 5.04
> (Hoary) and 5.10 (Breezy) here with DHCP and neither have any sort of
> issue like the one seen.  As a matter of fact, the machines do get the
> same IP address assigned each time I reboot them.
> I really suspect a problem with configuration or something on your end.
> That being said, it's strange that the problem is occurring on two
> different machines.
> Just out of curiosity, how do you know how long the server lease times
> are?  One other note, it's the server end that enforces the lease times
> not the client (your) end.  When your machine initializes its network
> via dhcp, it sends a DHCPDISCOVER request to the server.  When the
> server receives it, the MAC address is checked against existing leases
> and if one exists, the IP address from that lease is assigned.  You
> *can* be assigned a different IP address if the IP address you *were*
> assigned got re-assigned between the time you disconnected and when you
> reconnect.

I know how long the lease times are because that's what I set them to.  I'm 
the engineer who built the network.  I know how DHCP works.  What I'm saying 
is that I'm seeing a different behaviour from my Ubuntu box from any other 
box I've plugged into the network.  I DO NOT have this problem with any of 
the SuSE boxes I've plugged in in the past.  Just Ubuntu. 

> You mentioned that your ISP is complaining because they are running out
> of IP addresses to assign.  This would suggest that their DHCP server
> is, in fact, assigning you a different IP address because the one you
> had previously got re-assigned.

That wasn't me, that was the OP.  

> Take a look at /var/log/syslog.  There should be some entries tagged
> *dhclient*.  These should show the request and ack sequence exchange
> with the server.  It should also show the IP address assigned by
> the server and the renewal time (in seconds).  Post the info if you
> can.

That I haven't looked at.  I'll look at the logs and see what they are 
reporting.  This is more of an annoyance than anything else.  It's not 
anything crucial on my end at the moment.  I just saw the OP was having 
issues similar to what I was seeing, so I thought I'd post my problems as 

> --
> Michael J. Lynch
> What if the hokey pokey IS what it's all about -- author unknown

BOFH excuse #448:

vi needs to be upgraded to vii

More information about the ubuntu-users mailing list