[CentOS] firewall dilemma

Leonard Isham leonard.isham at gmail.com
Wed Nov 2 18:17:41 UTC 2005

On 11/2/05, JC <hiep at ee.ucr.edu> wrote:
> On Wed, 2 Nov 2005, Jim Bartus wrote:
> > JC wrote:
> > >  For example: I have web server (used internal ip behind the
> >>  firewall, internal network can access this web server with
> >>, but they can't access http://www.mydomain.com.  Assume
> >>  that I have static IP (xxx.xxx.xxx.xxx) maps to and dns record
> >>  www.mydomain.com points to xxx.xxx.xxx.xxx
> >>
> >>  What I want is to allow users inside the network be able to access
> >>  http://www.mydomain.com instead of
> >>
> >>  Here is my question:
> >>  should I change the rule of the firewall?  If so, is there a security
> >>  risk?
> >
> > What kind of firewall?  You should be able to add a simple rule that permits
> > incoming traffic from your non-NAT'd IP range.  Is your firewall also your
> > gateway/router or is there a separate device?  Where is the NAT occurring?
> >
> I have CISCO PIX 515E.  My DSL modem -> firewall -> router -> computers.
> That's all i have, no other device.  Now, can u show me what command I
> should  use to permit incoming traffic that originates from internal
> network???
> For now, i just use this method.  Is there any security risk involves in
> this method?
> I never setup DNS server before and have very little knowledge on DNS, so
> I don't want to use internal DNS for now, but I'll learn more about it.
> For know, I just want to get this problem solves.  Thank you for all you
> help.

Pix provides a solution for this dilemma the alias command:


If I understand your situation correctly this section specifically has
what you need:


Leonard Isham, CISSP
Ostendo non ostento.

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