Re: Does ICS or Firewall have a NAT

Your welcome.

Kerry

Descartes wrote:
> Thank you Joe, Steve and Kerry for all your input.
> I think I know now how to proceed.
>
> Best regards
> Descartes
>
>
> "Kerry Brown" <kerry@xxxxxxxxxxxxxxxxxxx*a*m> kirjoitti
> viestissä:ensnd0hGGHA.1028@xxxxxxxxxxxxxxxxxxxxxxx
>> Steve Winograd [MVP] wrote:
>>> In article <OzS9IrfGGHA.3936@xxxxxxxxxxxxxxxxxxxx>, "Kerry Brown"
>>> <kerry@xxxxxxxxxxxxxxxxxxx*a*m> wrote:
>>>> Descartes wrote:
>>>>>> Yes, ICS uses NAT.
>>>>>>
>>>>>> What do you mean by "static mapping"? What exactly do you want
>>>>>> to do? --
>>>>> Well I read somewhere, that a NAT creates a mapping of an intranet
>>>>> computers request out to the Internet. When a response arrives
>>>>> from the internet, the NAT looks in its mapping, to which intranet
>>>>> computer it should forward the response. This mapping is created
>>>>> dynamically and deleted when not needed anymore. The side effect
>>>>> of this is that the NAT actually works as a kind of fire wall
>>>>> neglecting all inbound traffic for which it does not have a
>>>>> mapping. This is all OK and does not require static mapping. But,
>>>>> if I would set up a server (on the intranet) to be accessible
>>>>> from the Internet, the NAT would need a static (persistent)
>>>>> mapping to know to which computer forward the requests coming
>>>>> from the Internet and addressed to the server.
>>>>> Please correct me if this doesn't make sens at all.
>>>>
>>>> Yes, ICS can do what you want. A stand alone router is a better
>>>> idea for a couple of reasons.
>>>
>>> I agree that a router is usually better than ICS, Kerry. But a
>>> router can't do the job if you're sharing a non-Ethernet Internet
>>> connection, like a dial-up modem or a USB cable modem.
>>>
>>>> 1) Using ICS the gateway computer is dirctly exposed to the
>>>> Internet on the public interface. A router will give all computers
>>>> some level of protection from malware. ICS will give all the other
>>>> computers this level of protection but the computer running ICS
>>>> will still be exposed.
>>>
>>> The ICS computer should be fine if it's running Windows Firewall.
>>> However, a router plus firewall gives two layers of protection.
>>>
>>
>> Two layers is always better.
>>
>>>> 2) The computer running ICS must be on for the other computers to
>>>> access the Internet. The computer running ICS will run slower
>>>> because of ICS. You may or may not notice this depending what else
>>>> the computer is used for.
>>>
>>> I can't imagine that ICS would have a noticeable effect. A typical
>>> broadband router has much less memory and a much slower processor
>>> than any computer that can run XP. For example, my SMC Barricade
>>> router has a 40 MHz CPU and less than 1MB of memory
>>>
>>
>> I have seen otherwise respectable machines have a noticable slowdown,
>> especially when dialing, when a some winmodems are used with ICS. As
>> you say normally not a problem, but it can be noticable.
>>
>> Kerry



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