[gentoo-user] Internet providers' IP range (xinetd.conf)

[gentoo-user] Internet providers' IP range (xinetd.conf)

[Helmut Jarausch]

Hi,

I'd like to allow remote access (via ssh only) to a given machine.
Unfortunately, my remote IP is dynamic and reverse lookup
(e.g. specifying only_from = .skynet.be in /etc/xinetd.conf) doesn't work.
So, I have to find out which IP ranges are used by a given
internet provider (e.g. skynet.be).

Does anybody know how to find out?

Many thanks for a hint,
Helmut.

-- 
Helmut Jarausch
RWTH-Aachen University
Germany

Re: [gentoo-user] Internet providers' IP range (xinetd.conf)

[Paul Hartman]

On Wed, Sep 2, 2009 at 9:11 AM, Helmut Jarausch<jarausch@skynet.be> wrote:
> Hi,
>
> I'd like to allow remote access (via ssh only) to a given machine.
> Unfortunately, my remote IP is dynamic and reverse lookup
> (e.g. specifying only_from = .skynet.be in /etc/xinetd.conf) doesn't work.
> So, I have to find out which IP ranges are used by a given
> internet provider (e.g. skynet.be).
>
> Does anybody know how to find out?
>
> Many thanks for a hint,
> Helmut.

Easiest way: ask them to tell you the ranges :) Otherwise would be
guessing. You can look at arin (or local equivalent) to see which IP
range(s) they own. But nobody knows for sure other than them.

[gentoo-user] Re: Internet providers' IP range (xinetd.conf)

[walt]

On 09/02/2009 07:11 AM, Helmut Jarausch wrote:
> Hi,
>
> I'd like to allow remote access (via ssh only) to a given machine.
> Unfortunately, my remote IP is dynamic and reverse lookup
> (e.g. specifying only_from = .skynet.be in /etc/xinetd.conf) doesn't work.
> So, I have to find out which IP ranges are used by a given
> internet provider (e.g. skynet.be).
>
> Does anybody know how to find out?

Here's a quick and dirty trick:

$host skynet.be
skynet.be has address 195.238.10.70

$whois -H 195.238.10.70
<snip>
% Information related to '195.238.0.0 - 195.238.31.255'
inetnum:        195.238.0.0 - 195.238.31.255
netname:        SKYNET-B
descr:          Belgacom SA/NV
descr:          Internet access provider

As Paul said, though, asking them is more accurate.

Re: [gentoo-user] Internet providers' IP range (xinetd.conf)

[Alan McKinnon]

On Wednesday 02 September 2009 21:11:20 Paul Hartman wrote:
> On Wed, Sep 2, 2009 at 9:11 AM, Helmut Jarausch<jarausch@skynet.be> wrote:
> > Hi,
> >
> > I'd like to allow remote access (via ssh only) to a given machine.
> > Unfortunately, my remote IP is dynamic and reverse lookup
> > (e.g. specifying only_from = .skynet.be in /etc/xinetd.conf) doesn't
> > work. So, I have to find out which IP ranges are used by a given
> > internet provider (e.g. skynet.be).
> >
> > Does anybody know how to find out?
> >
> > Many thanks for a hint,
> > Helmut.
>
> Easiest way: ask them to tell you the ranges :) Otherwise would be
> guessing. You can look at arin (or local equivalent) to see which IP
> range(s) they own. But nobody knows for sure other than them.

Two solutions:

1. Put your host into dyndns and ssh to that name

2. You can ask peering routers for an ISP's IP range (it's public info and has 
to be that way). I forget the exact commands, but a mail thread on a different 
list covered this exact thing a while ago. You'll have to search the Glug-tech 
mail archives at http://www.linux.org.za/Lists-Archives/ from about 6 to 9 
months back.

Relevant search terms are "jinx" and "jaco kroon"

-- 
alan dot mckinnon at gmail dot com

Re: [gentoo-user] Internet providers' IP range (xinetd.conf)

[Kyle Bader]

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>
> 1. Put your host into dyndns and ssh to that name
>

I'll often do this and then create a subdomain of a domain I own then have
it CNAME to the dyndns domain name.  I find that I have a easier time
remembering the names I choose this way.

-- 

Kyle

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Re: [gentoo-user] Re: Internet providers' IP range (xinetd.conf)

[Mick]

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On Wednesday 02 September 2009, walt wrote:
> On 09/02/2009 07:11 AM, Helmut Jarausch wrote:
> > Hi,
> >
> > I'd like to allow remote access (via ssh only) to a given machine.
> > Unfortunately, my remote IP is dynamic and reverse lookup
> > (e.g. specifying only_from = .skynet.be in /etc/xinetd.conf) doesn't
> > work. So, I have to find out which IP ranges are used by a given
> > internet provider (e.g. skynet.be).
> >
> > Does anybody know how to find out?
>
> Here's a quick and dirty trick:
>
> $host skynet.be
> skynet.be has address 195.238.10.70
>
> $whois -H 195.238.10.70
> <snip>
> % Information related to '195.238.0.0 - 195.238.31.255'
> inetnum:        195.238.0.0 - 195.238.31.255
> netname:        SKYNET-B
> descr:          Belgacom SA/NV
> descr:          Internet access provider
>
> As Paul said, though, asking them is more accurate.

Most ISPs have a web accessible control panel which should indicate which IP 
address you currently have.  Alternatively, you can have your home 
server/router pinging an external server every 15 minutes or so and check the 
incoming logs of the external server for the change of the incoming IP 
address.  The DynDNS solution must be the simplest though.
-- 
Regards,
Mick

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