[gentoo-user] DHCP - specific inet no - how to

[gentoo-user] DHCP - specific inet no - how to

[Helmut Jarausch]

Hi,

I have a small local network with local Inet numbers 192.168.1.x .
How can I request a specific Inet number for a given device  
(PC,printer).
Normally, a device tries to get the previous inet number, but sometime  
this
changes. I'd like to assign fix adresses since the net is used by only  
a few device.
But I cannot configure the DHCP server myself since this is provided by  
my internet provider.

Many thanks for a hint,
Helmut.

Re: [gentoo-user] DHCP - specific inet no - how to

[Andrea Conti]

Hello,

> Normally, a device tries to get the previous inet number, but sometime this
> changes.

DHCP clients can neither request nor suggest a specific IP address, so
they don't "try to get" anything. It's just the DHCP server giving out
the previous IP to the same client, either by chance or because the
existing lease hasn't expired yet.

> But I cannot configure the DHCP server myself since this is provided by
> my internet provider.

Then you're basically out of luck. Since you have few devices and those
devices are under your control, just forget about DHCP and configure
them statically.

andrea

Re: [gentoo-user] DHCP - specific inet no - how to

[Helmut Jarausch]

On 11/08/2012 09:18:35 AM, Andrea Conti wrote:
> Hello,
> 
> > Normally, a device tries to get the previous inet number, but  
> sometime this
> > changes.
> 
> DHCP clients can neither request nor suggest a specific IP address, so
> they don't "try to get" anything. It's just the DHCP server giving out
> the previous IP to the same client, either by chance or because the
> existing lease hasn't expired yet.
> 
> > But I cannot configure the DHCP server myself since this is  
> provided by
> > my internet provider.
> 
> Then you're basically out of luck. Since you have few devices and  
> those
> devices are under your control, just forget about DHCP and configure
> them statically.

Thanks!
But I get the nameserver of DHCP, as well. Can this be fetched from  
DHCP since this may change?

 From man dhclient
  A DHCP client may request an address from this pool,  and  then
  use  it  on  a temporary basis for communication on network
I've just not found out howto.

Helmut.

Re: [gentoo-user] DHCP - specific inet no - how to

[Neil Bothwick]

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On Thu, 08 Nov 2012 09:18:35 +0100, Andrea Conti wrote:

> > Normally, a device tries to get the previous inet number, but
> > sometime this changes.  
> 
> DHCP clients can neither request nor suggest a specific IP address, so
> they don't "try to get" anything. It's just the DHCP server giving out
> the previous IP to the same client, either by chance or because the
> existing lease hasn't expired yet.

dhcpcd has a --resquest option to do just this. It only works if the
address is available and if the server is returning a different address
now it may be that your preferred address is in use.

Have you considered running a local DHCP server, like dnsmasq?


-- 
Neil Bothwick

WinErr 01C: Uncertainty error - Uncertainty may be inadequate.

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Re: [gentoo-user] DHCP - specific inet no - how to

[Helmut Jarausch]

On 11/08/2012 09:45:34 AM, Neil Bothwick wrote:
> On Thu, 08 Nov 2012 09:18:35 +0100, Andrea Conti wrote:
> 
> > > Normally, a device tries to get the previous inet number, but
> > > sometime this changes.
> >
> > DHCP clients can neither request nor suggest a specific IP address,  
> so
> > they don't "try to get" anything. It's just the DHCP server giving  
> out
> > the previous IP to the same client, either by chance or because the
> > existing lease hasn't expired yet.
> 
> dhcpcd has a --resquest option to do just this. It only works if the
> address is available and if the server is returning a different  
> address
> now it may be that your preferred address is in use.
> 
> Have you considered running a local DHCP server, like dnsmasq?

Thanks Neil!
I have router (provided by my internet provider) which can be accessed  
by WLAN.
Since I cannot modify/configure this router how can I make use of  
dnsmasq ?

Helmut.

Re: [gentoo-user] DHCP - specific inet no - how to

[Neil Bothwick]

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On Thu, 08 Nov 2012 12:13:56 +0100, Helmut Jarausch wrote:

> > Have you considered running a local DHCP server, like dnsmasq?  
> 
> I have router (provided by my internet provider) which can be accessed  
> by WLAN.
> Since I cannot modify/configure this router how can I make use of  
> dnsmasq ?

Good question! Can you not even disable the DHCP server in the router?


-- 
Neil Bothwick

Inland Revenue: We've got what it takes to take what you've got!

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Re: [gentoo-user] DHCP - specific inet no - how to

[J. Roeleveld]

On Thursday, November 08, 2012 12:13:56 PM Helmut Jarausch wrote:
> On 11/08/2012 09:45:34 AM, Neil Bothwick wrote:
> > On Thu, 08 Nov 2012 09:18:35 +0100, Andrea Conti wrote:
> > > > Normally, a device tries to get the previous inet number, but
> > > > sometime this changes.
> > > 
> > > DHCP clients can neither request nor suggest a specific IP address,
> > 
> > so
> > 
> > > they don't "try to get" anything. It's just the DHCP server giving
> > 
> > out
> > 
> > > the previous IP to the same client, either by chance or because the
> > > existing lease hasn't expired yet.
> > 
> > dhcpcd has a --resquest option to do just this. It only works if the
> > address is available and if the server is returning a different
> > address
> > now it may be that your preferred address is in use.
> > 
> > Have you considered running a local DHCP server, like dnsmasq?
> 
> Thanks Neil!
> I have router (provided by my internet provider) which can be accessed
> by WLAN.
> Since I cannot modify/configure this router how can I make use of
> dnsmasq ?
> 
> Helmut.

Are you not able to use your own router?

Being able to configure the DHCP and NAT-configuration of the router is often 
required to get certain software to work. There are multi-player games that 
need ports forwarded to be able to play with other people over the internet. 
(Just to name a common scenario)

--
Joost

Re: [gentoo-user] DHCP - specific inet no - how to

[Mick]

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On Thursday 08 Nov 2012 13:15:27 J. Roeleveld wrote:
> On Thursday, November 08, 2012 12:13:56 PM Helmut Jarausch wrote:
> > On 11/08/2012 09:45:34 AM, Neil Bothwick wrote:
> > > On Thu, 08 Nov 2012 09:18:35 +0100, Andrea Conti wrote:
> > > > > Normally, a device tries to get the previous inet number, but
> > > > > sometime this changes.
> > > > 
> > > > DHCP clients can neither request nor suggest a specific IP address,
> > > 
> > > so
> > > 
> > > > they don't "try to get" anything. It's just the DHCP server giving
> > > 
> > > out
> > > 
> > > > the previous IP to the same client, either by chance or because the
> > > > existing lease hasn't expired yet.
> > > 
> > > dhcpcd has a --resquest option to do just this. It only works if the
> > > address is available and if the server is returning a different
> > > address
> > > now it may be that your preferred address is in use.
> > > 
> > > Have you considered running a local DHCP server, like dnsmasq?
> > 
> > Thanks Neil!
> > I have router (provided by my internet provider) which can be accessed
> > by WLAN.
> > Since I cannot modify/configure this router how can I make use of
> > dnsmasq ?
> > 
> > Helmut.
> 
> Are you not able to use your own router?
> 
> Being able to configure the DHCP and NAT-configuration of the router is
> often required to get certain software to work. There are multi-player
> games that need ports forwarded to be able to play with other people over
> the internet. (Just to name a common scenario)
> 
> --
> Joost

Do you get a GUI when go to your routers LAN address with a browser, or a 
request for username when you telnet/ssh to it?  If yes, you can try the 
various default passwords to see if you can log in, like admin, password, and 
others that google may advise as suitable candidates.

Then you can try to set it up as a bridged-modem and do the routing and PPPoE 
authentication using a separate router as already advised.

If this fails then contacting your ISP for advice on configuring your router 
may also be an option.
-- 
Regards,
Mick

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Re: [gentoo-user] DHCP - specific inet no - how to

[Andrea Conti]

> dhcpcd has a --resquest option to do just this.

One never stops learning...

> It only works if the
> address is available and if the server is returning a different address
> now it may be that your preferred address is in use.

It also depends on the dhcp server understanding the request. I don't
know if the option is actually a required part of the DHCP protocol, and
as implemented even in cheap telco routers... although many routers
these days run some sort of embedded linux with dnsmasq.

andrea