[lug] Hostname, Knoppix, where does it come from?
bcollins at peakpeak.com
Thu Jun 29 21:13:53 MDT 2006
Nate Duehr wrote:
> On Jun 28, 2006, at 8:42 PM, Bob Collins wrote:
>> Ed Moxley wrote:
>>> On Wed, 2006-06-28 at 17:06, Bob Collins wrote:
>>>> I decided to install a fresh version of SuSE 10.0. Everything went
>>>> fine except that this is what I get when I ping from another
>>>> computer on my local network. bob at matt:~> ping linux.local PING
>>>> linux.local (192.168.0.67) 56(84) bytes of data. 64 bytes from
>>>> Knoppix (192.168.0.67): icmp_seq=1 ttl=64 time=0.139 ms 64 bytes
>>>> from Knoppix (192.168.0.67): icmp_seq=5 ttl=64 time=0.167 ms
>>> Do you really want the box to be called linux.local? You might try
>>> changing back to dhcp from the static config and changing the host
>>> name to a single name like linuxwhatever (without the dot) and see
>>> if the Knoppix name goes away.
>> Linux is not a good name for a computer box, but it has had that name
>> for many years. All of the computers on my local area network have
>> the the box_name.domain_name where domain_name is local. I add the
>> .local to linux in the email because of the other meanings for linux,
>> which makes it confusing.
>> Tech support at peakpeak.com answered my email by saying I should
>> contact Novell/SuSE tech support. I copied another person there who
>> seems to know a little more about linux and what is going on, but I
>> really don't expect much help from peakpeak.com.
>> I should have checked them out a little better, but I am sure they
>> are not as bad as msm.com, the Qwest default internet provider.
>> Thank you all for your help.
> Here's my 3AM comments. Hope they're not too rambling and make at
> least a little sense to you after posting at this horrible hour.
> (Can't sleep.)
> From many years of experience with DNS -- and making some assumptions
> about how your 2wire brand router works, I'd say the following happened:
> First off, your router is apparently acting as your local DNS server
> for anything on your internal LAN subnet, and it hands out it's own IP
> address for serving DNS requests in the initial DHCP request from your
> clients. (This is pretty easy to check - if all your DHCP clients
> show your router's internal IP address as their DNS server, that's
> what it's doing.) MANY small router/firewalls do this nowadays to
> make setup easy for everyone - no more setting up a DNS server in the
> router - it just proxy's the requests.
> You booted Knoppix and its DHCP client has the relatively (many years,
> but...) new feature turned on that not only asks the router for an
> internal private IP address, but also sends a DNS update packet using
> it's machine name to the router.
> Your router now believes that's the name of the machine on that
> particular internal IP address. It also appears that your router
> "splits" your DNS and keeps track of machine names internally using
> the 2wire.com domain name internally also. (You don't own or operate
> the 2wire.com domain and theoretically should have no possible way to
> update/add/change it. So assuming 2wire isn't doing some kind of free
> dynamic DNS service for all of their routers -- which I very highly
> doubt -- this naming phenomenon is limted to your local LAN behind the
> 2wire router. No one "on the Internet" can see or use any of the DNS
> names you've mentioned from the outside world of the Internet itself.)
> Okay having worked on a couple of 2wire routers before I can say two
> things about them. They're set up by default to make it virtually
> impossible for a user to screw up their Internet connectivity -- they
> make all the "choices" you should be making for yourself about your
> network for you. Second, they usually have an "Advanced" mode where
> you can override certain behaviors, but it wouldn't surprise me at all
> if they didn't provide a way to turn this auto-DNS junk off internally.)
> So, a couple of thoughts...
> Did you try rebooting the 2wire router? If you're lucky and they
> don't store DHCP information in non-volatile memory (flash), perhaps
> it'll simply "forget" it ever knew a name for that IP address after a
> Next, you could always turn on the same feature that Knoppix is using
> to update DNS from your other Linux. If Knoppix can set/change the
> name in the router during its DHCP sessions, so can your other Linux.
> How easy or difficult that might be is probably something you'd need
> to research, but I'd start with Googling for "Dynamic DNS + DHCP +
> <Distro name>" and going from there. It's probably relatively easy to
> tell your SuSE to do it, but I've never done it on SuSE, so I can't
> elaborate at all.
> Finally -- the simplest question... why do you care what the 2wire
> router calls the machine on your internal LAN? If the early
> assumption is correct that 2wire doesn't "publish" this name in any
> way out to the Net, it simply doesn't matter. You can put a hosts
> file entry on the other machines to give that machine ten different
> names that work that you can call it by, other than the one you don't
> like... or you could even set up an internal DNS server if there is
> some way to tell the 2wire NOT to hand out its own IP address as a DNS
> server for your internal LAN. I doubt they give you this option, the
> 2wire routers are pretty limited, trying to make things "easier" on
> you. All they accomplish is making it SO easy, you don't really know
> what's going on and missed a number of key things like learning how
> hostnames and DNS resolve, which is pretty basic core networking
> To summarize: Don't worry about it. Use the real IP address or add a
> hosts file entry or two to call it what you want on your internal
> network. If you REALLY want to know how to straighten it out, you're
> going to have to do the research to figure out how Knoppix set it in
> the first place and duplicate the effort on SuSE. Linux is Linux, so
> it *can* be done, but it may be easy (if the feature is built-in to
> SuSE and just not enabled) or difficult (have to find and build the
> DHCP client Knoppix is using if your SuSE's version won't do it).
> The only other serious comment I might offer is this: If you want to
> learn how something like networking, routing and DHCP work, including
> the DNS server assignment, etc... the absolute best way would be to
> find everything labeled "Auto" in the 2wire and set it to manual --
> and attempt to build your network from the ground up, and get it
> working, with all static IP's, hostnames, perhaps a DNS server... if
> you feel like purchasing a domain name, etc... everything set up and
> configured by YOU, not the engineer that built the 2wire router --
> they built it to do everything for you but butter your morning
> toast... and it sounds like it's doing just that... anytime a computer
> isn't doing what you want it to, do like you just did and dive in with
> both feet and figure out why -- it's only doing what it was programmed
> or told to do by *someone*... in this case, it certainly sounds like
> that would be the 2wire engineers.
> It also sounds like peakpeak.com has NOTHING to do with what you're
> seeing -- other than choose a really cheesy hard-to-configure-manually
> router for their customers. But I guarantee they did it to keep
> setups simple and installation easy and to save themselves having to
> directly support users needing assistance with network setup.
> Oh yeah, the reason your ping is even showing a name on the replies is
> that your client doing the ping is doing a reverse DNS lookup on the
> internal address of your linux machine. The 2wire is just handing it
> the name it knows about. Changing the machine's internal address
> could/should allow you to work from an IP that 2wire knows no
> information about.
> Nate Duehr
> nate at natetech.com
> Web Page: http://lug.boulder.co.us
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Thank you for your words of wisdom. It must be the practice you had
getting ready for finals. You seemed lucid to me. I decided to change
the range of DHCP addresses and eliminate the old addresses. This seems
to have fixed the problem, if you can call it a problem.
I don't think the DSL modem can forget an address and what it learns
about it. Even if it is wrong.
As for the reason I care about it, I suppose I am more than a little
Thanks to everyone who offered help. I appreciate it.
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