[luau] dhcp-146-41

W. Wayne Liauh LiauhW001 at Hawaii.rr.com
Mon Dec 23 16:37:00 PST 2002


The following is the comment that I sent to a kind LUAU member who 
responded to my question in private.  I believe the situation is in a 
total mess (and I envy those Windows cable modem users who are being 
totally screwed up without an opportunity to realize it).  More 
specifically, as per George's comment, it appears that Red Hat's dhcp 
client configuration allows the RoadRunner router to alter your hostname 
(which should be a very big no no, in light of the problems that I had 
experienced).  OTOH, it also appears that, for very strange reasons, 
some RoadRunner dhcp servers (e.g., the one connected to my house) do 
not attempt to change the hostname. A public dhcp server is supposed to 
"lease" you a temporary ip address.  No thing more.  Anything beyond 
that and we may have someone committing criminal activities upon us.


"It appears that this particular RR router is doing what it is NOT 
supposed to do (trying to take control of the computer but leaving no 
host address; and believe me, we have reformatted the HD several times.)

"Previously this PC was running Win98 and was "on" all the time (while 
connected to RR).  I suspect whether anyone is trying to take advantage 
of their vulnerability?  Althogh I just don't think how this could be 
possible.  Previously, the Win98 system had deteriorated to a stage that 
it was almost imoperatable (it is a very powerful system, and its owner 
was doing nothing but browsing and emailing)."



Ray Strode wrote:

> Not sure why it's causing so many problems, but I can explain a little 
> bit about how the process works on
> redhat.
>
> First, the computer requests an ip from the dhcp server (called DHCP 
> request), then
> dhcp server returns the computer's ip address and other network 
> information, including the dns server
> (called DHCP ACK [ACK is for acknowledgment]).  Some time during this 
> process the file
> /etc/sysconfig/network gets sourced and certain environment variables 
> are set. 
> If HOSTNAME is one of the environment variables to get set and it is 
> set to something other than
> "" or "localhost", then the hostname of the system is set to $HOSTNAME.
>
> If HOSTNAME is not set, or it is set to "" or "localhost"  then the 
> computer performs a reverse lookup on the ip
> it was just given (by asking the dns server it was just told about). 
> Whatever results from this reverse lookup is the
> hostname assigned to the system.  If the reverse lookup fails, then 
> the hostname is set to localhost.  --Ray
>
>
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