Archived from groups: comp.security.firewalls (
More info?)
If I don't want anything to initiate access to my network from outside,
besides normal responses to HTTP and SMTP requests, do I need to go beyond
NAT? If there's no server or remote access going on?
Thanks,
tslug
On Tue, 03 Aug 2004 21:59:36 GMT, Leythos <void@nowhere.com> wrote:
> In article <opsb6dyxrnk1tkce@tslugmo.belkin>, anon@yeahright.com says...
>> I was wondering if somebody could clarify the difference between a cheap
>> retail firewall, like a D-Link you might get at Staples, with
>> professional
>> grade firewalls from Symantec or Watchguard.
>
> You need to separate the idea that a router with NAT is a firewall from
> what a real firewall is/does. Routers with NAT provide a blocking
> service based on the NAT function, nothing else.
>
> Firewalls may or may not use NAT and provide filtering of traffic based
> on traffic type (not always a port number) and do it in both directions.
>
> There is a huge difference between a router with NAT and a firewall of
> any type.
>
>> If there is no serving going
>> on behind the firewall, (ie, no virtual server passthrough), is there
>> really a difference in security? Doesn't this eliminate the need for
>> SPI? Are $600 firewalls harder to defeat than $40 firewalls? Is it
>> just
>> the bells and whistles of logging and alerts?
>
> Yes, in one case, there was as sorority that had a NAT system installed,
> there were 6 machines that were infected with a virus that had it's own
> SMTP server. The infected machines were sending out infected emails
> directly form their systems, bypassing the internal SMTP server. Had a
> real-firewall been installed (or properly configured high-end router)
> SMTP would not have been permitted from the local devices (except the
> SMTP server) to the internet, or it would have only been permitted from
> the workstations to the ISP's SMTP server for outbound messages. A
> generic router would not have prevented this problem from reaching the
> world.
>
> $600 firewalls, or any firewall that is a real firewall, is harder to
> defeat when properly configured than ANY router with NAT and SPI or any
> router with just NAT.
>
> If you've been reading these groups for a couple weeks you would already
> know this :-)
>
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