static ip address and ifconfig

Fbsd8 fbsd8 at a1poweruser.com
Sat Dec 29 18:45:54 UTC 2012


Polytropon wrote:
> On Sat, 29 Dec 2012 13:05:30 -0500, Fbsd8 wrote:
>> Mike Jeays wrote:
>>> On Sat, 29 Dec 2012 12:13:32 -0500
>>> Fbsd8 <fbsd8 at a1poweruser.com> wrote:
>>>
>>>> I don't have static ip address so I can not find out for myself.
>>>> Lets say I am a company that my ISP has assigned us
>>>> 25 static ip address.
>>>>
>>>> When I issue the ifconfig command what will it show me?
>>>>
>>>> Just the single primary static ip address or all 25 of them in a list?
>>>>
>>>> Thanks
>>>> _______________________________________________
>>> It will just show the one currently assigned.
>>>
>>> Try it - just bring up an xterm and type 'ifconfig' You don't have to 
>>> be root, and you can't do any harm.
>>>
>>>
>>> em0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
>>> 	options=9b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM>
>>> 	ether 08:00:27:40:ca:a9
>>> 	inet 10.0.2.15 netmask 0xffffff00 broadcast 10.0.2.255  # HERE IT IS
>>> 	media: Ethernet autoselect (1000baseT <full-duplex>)
>>> 	status: active
>>>
>> Nope 10.0.2.15 is a private lan IP address, its not public routable.
>> question has to be answered by some body who has multiple static public 
>> routable ip address assigned by their ISP.
> 
> The presented example simply shows a typical ifconfig output.
> On the "inet" line, you can see the assigned IP addresses.
> As per definition, one interface can be assigned more than
> one IP address, and maybe those will show in the ifconfig
> output - however, this depends on your actual setup, for
> example when you have specific network gear that "translates"
> one or more static IP addresses into local addresses that
> are _then_ assigned to individual network interfaces.
> 
> However, at my old location I had assigned one static IP
> address directly delivered to the NIC, and ifconfig did
> show exactly that address.
> 
> Simply try "ifconfig" and show what it prints for YOU.
> 

Yes I understand all that, but lets go deeper into difference between 
static and dynamic ip address assigned by the ISP.

For anyone being a professional company who wants permanent presents on 
the internet will pay extra fees for static ip
address because static ip address never change and this is required for
domain name registration. Dynamic ip address are normally assigned by the
ISP for home users having dsl or tv cable internet connections. Dynamic
ip address can change and if used for domain name registration the users
FQDN will no longer point to the correct host.

Now to return to the original question.
Say I am a professional company and my ISP assigned me 25 static ip address.
What will ifconfig show me on the interface facing the public internet?
Just the single primary static ip address or all 25 of them in a list?




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