Dynamic IP address and hostname

Dynamic IP address and hostname

Post by Topher Cawlfiel » Sat, 13 Feb 1999 04:00:00



Hi,

I am setting up Linux on my computer at home, and am not sure how to best
configure it for my dialup service.  I am using RH 5.2, and have (finally)
gotten the ppp configuration working.  When I dial in, I am given a
(dynamic) IP address, but I have a hard time figuring out what it is so
that I can, for example, launch X-applications from other computers.

I am also not quite sure what the best way is to name my computer, but I
think it might relate to the mystery dynamic IP.  The network I'm dialing
into has the domain name hep.uiuc.edu (for example).  Wouldn't it be great
if I could be (as reported by hostname), say, peon.localhost normally, and
then suddenly peon.hep.uiuc.edu when I "go online".  Maybe I could even
telnet to another computer, and automatically have my DISPLAY variable set
correctly!

This is a kind of strange question because I don't really know what I'm
asking.  I guess I'm just looking for advice from others who are using
their computer in a simmilar way that I am, and have things configured the
way they like it.

 - Topher Cawlfield

p.s.  I sound clueless in this post, but I really have a great deal of
experience *using* Unix (OSF1, IRIX, HPUX, AIX, and Solaris, mostly).  But
I am new to Linux, and am new to system administration which I find is an
entirely different skill alltogether.

 
 
 

Dynamic IP address and hostname

Post by scre.. » Sat, 13 Feb 1999 04:00:00


On Fri, 12 Feb 1999 12:50:29 -0600, Topher Cawlfield


>Hi,

>I am setting up Linux on my computer at home, and am not sure how to best
>configure it for my dialup service.  I am using RH 5.2, and have (finally)
>gotten the ppp configuration working.  When I dial in, I am given a
>(dynamic) IP address, but I have a hard time figuring out what it is so
>that I can, for example, launch X-applications from other computers.

You can type ifconfig to show your currently configured interfaces.
Your ppp interface will be (probably) ppp0.  Off the top of my head,
your Internet address will be the one label inet addr. :)  That's the
way it is here at on eth0, and I think the two interface will display
the same.

Quote:>I am also not quite sure what the best way is to name my computer, but I
>think it might relate to the mystery dynamic IP.  The network I'm dialing
>into has the domain name hep.uiuc.edu (for example).  Wouldn't it be great
>if I could be (as reported by hostname), say, peon.localhost normally, and
>then suddenly peon.hep.uiuc.edu when I "go online".  Maybe I could even
>telnet to another computer, and automatically have my DISPLAY variable set
>correctly!

You can name your machine anything you want (with certain restrictions
imposed by the OS, obviously), but the only way for that machine to be
visible by its name from the Internet is if you can register your
machine with a name server somewhere.  This is much easier if you have
a static IP and a sympathetic DNS admin.  With a dynamic IP, you can
do this through a number of services such as ddns.org and dyndns.com.
These services, however, will associate your dynamic IP with a machine
name on their network, so your machine will appear as foo.ddns.org,
for example.  Your school will need to run a similar service to allow
your machine a name on their network.

I use ddns.org, but not just real happy with it.  Lookups tend to fail
all the time.  I haven't pinned down a pattern to it, and I have no
clue as to the cause, but I'm looking at slapping down the $25 that
dyndns.org (?) wants per year.  HTH.

Jason

 
 
 

Dynamic IP address and hostname

Post by Matt Kresse » Sat, 13 Feb 1999 04:00:00



> Hi,

> I am setting up Linux on my computer at home, and am not sure how to best
> configure it for my dialup service.  I am using RH 5.2, and have (finally)
> gotten the ppp configuration working.  When I dial in, I am given a
> (dynamic) IP address, but I have a hard time figuring out what it is so
> that I can, for example, launch X-applications from other computers.

Run the command "ifconfig ppp0" after connecting.

Quote:> I am also not quite sure what the best way is to name my computer, but I
> think it might relate to the mystery dynamic IP.  The network I'm dialing
> into has the domain name hep.uiuc.edu (for example).  Wouldn't it be great
> if I could be (as reported by hostname), say, peon.localhost normally, and
> then suddenly peon.hep.uiuc.edu when I "go online".  Maybe I could even
> telnet to another computer, and automatically have my DISPLAY variable set
> correctly!

Doing remote X apps over a standard modem is annoyingly slow.  Also,
since you are getting a dynamic address, a DNS entry may already exist
for your IP address.  Do a "nslookup x.x.x.x" on your new IP address
(from ifconfig above) where x.x.x.x is the IP address of the ppp0
interface.  This will tell you your "temporary" (i.e. dynamic) hostname

Quote:

> This is a kind of strange question because I don't really know what I'm
> asking.  I guess I'm just looking for advice from others who are using
> their computer in a simmilar way that I am, and have things configured the
> way they like it.

-Matt

--

+---------  Northrop Grumman Corporation, Bethpage, NY ---------+
+---------  TEL: (516) 346-9101 FAX: (516) 346-9740 ------------+

 
 
 

Dynamic IP address and hostname

Post by Ross Crawfor » Mon, 15 Feb 1999 04:00:00




> > Hi,

> > I am setting up Linux on my computer at home, and am not sure how to best
> > configure it for my dialup service.  I am using RH 5.2, and have (finally)
> > gotten the ppp configuration working.  When I dial in, I am given a
> > (dynamic) IP address, but I have a hard time figuring out what it is so
> > that I can, for example, launch X-applications from other computers.

> Run the command "ifconfig ppp0" after connecting.

If you want to do it automagically, you can put whatever code you want in the
ip-up script. One of the parameters ($4 from memory) is the IP assigned by your
ISP.

Regards,

ROSCO

 
 
 

1. Dynamic IP addresses and fixed hostname

Hi all,

This might not be the correct group to post, but I think it might
be useful to someone...

I've been developing a system to allow UNIX hosts who connect with a
dynamic IP address from a provider, to have a fixed fully qualified domain
name, whatever is their IP address.

The primary stage is finished, and the system seems to be working allright
and effectively. Though it is still in beta testing.

If anyone is connecting a FreeBSD/Linux/Other system to the Internet with a
Dynamic IP address, and would like to have a permanent address, please feel
free to visit our Web site and try DHIS. The service is provided free of
cost.

        http://www.osdr.eu.org/osdr/dhis/

Thanks,
Joao Cabral.

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