RE: one external IP to multiple internal IPs? Ideas?

Sorry Brad, no joy... here's the problem:

The client (web browser) queries the DNS server for the IP address of the
web server. Now, you'll have the following DNS setup:

DNS server for company1.com knows about subdomain cso.company1.com and knows
addresses from this sub-domain can be determined from the DNS server at
209.83.29.5 (your DNS)

DNS server for company2.com knows about subdomain cso.company2.com and knows
addresses from this sub-domain can be determined from the DNS server at
209.83.29.5 (your DNS)

So, me as the web browser tries to resolve www.cso.company1.com and asks my
DNS server for the address. My DNS server doesn't know the answer so it
looks to the root dns servers for the answer. The root servers direct my DNS
server to the DNS server for company1.com. Company1.com's DNS server
receives a request for www.cso.company1.com and says "I can't answer this,
but 209.83.29.5 can" and my DNS server asks 209.83.29.5 for the correct IP
address. 

Now, you control 209.83.29.5 so you would think you could hand back the
correct 172.25.6.x address, and you're right you can. HOWEVER, I as a client
don't know how to get to 172.25.6.x as it is an internal-only address, I can
only get to 218.1.1.2. So you are back at square one. You must hand out
addresses that I can route to and then have your router re-route these
external addresses to internal addresses. 

Sorry.

-Walden


-----Original Message-----
From: Stone, Brad V (TC) [mailto:bvstone@taylorcorp.com]
Sent: Tuesday, May 09, 2000 8:45 AM
To: 'MIDRANGE-L@midrange.com'
Subject: RE: one external IP to multiple internal IPs? Ideas?


Yes, we have those set up, but they are in our DMZ.  So, they must point to
an external IP.  Then, the firewall routes that IP to a sigle IP inside our
firewall.  What I wish we could do (and I'm sure there's a way but don't
know enough about it) is to send the DNS name to an internal entry behind
our firewall, thus, sending a single IP to multiple internal IPs.

Any networking experts out there?  ;)

Brad

> -----Original Message-----
> From: Chris Bipes [mailto:rpg@cross-check.com]
> Sent: Monday, May 08, 2000 4:30 PM
> To: 'MIDRANGE-L@midrange.com'
> Subject: RE: one external IP to multiple internal IPs? Ideas?
> 
> 
> Do you have separate domain entries in your DNS system.  i.e..
> Serv1.domain.com, Serv2.domain.com....  Each of these can and should a
> unique IP address.  This should not be done via the router 
> but via the DNS
> server.  I am NOT an expert on this but it is my 
> understanding that this is
> how it all is suppose to work.  I know we have several 
> domains coming to our
> router and from there to the proper server based on the DNS 
> lookup.  The one
> internal that the router points to should be the DNS server.
> 
> Christopher K. Bipes   mailto:ChrisB@Cross-Check.com
> Sr. Programmer/Analyst         mailto:Chris_Bipes@Yahoo.com
> CrossCheck, Inc.       http://www.cross-check.com
> 6119 State Farm Drive  Phone: 707 586-0551 x 1102
> Rohnert Park CA  94928 Fax: 707 586-1884
> 
> If consistency is the hobgoblin of little minds, only 
> geniuses work here.
> Karen Herbelin - Readers Digest 3/2000
> 
> 
> -----Original Message-----
> From: Stone, Brad V (TC) [mailto:bvstone@taylorcorp.com]
> Sent: Monday, May 08, 2000 11:38 AM
> To: 'MIDRANGE-L@midrange.com'
> Subject: RE: one external IP to multiple internal IPs? Ideas?
> 
> 
> But the guys that have the router say I can't map more than 
> one internal IP
> to one external IP.
> 
> Brad
> 
> > -----Original Message-----
> > From: Chris Bipes [mailto:rpg@cross-check.com]
> > Sent: Monday, May 08, 2000 12:52 PM
> > To: 'MIDRANGE-L@midrange.com'
> > Subject: RE: one external IP to multiple internal IPs? Ideas?
> > 
> > 
> > Look like the best approach to me.  You may also want to 
> bind this IP
> > address to one particular interface if you have more than one 
> > on the system.
> > I prefer to have internal telnet to one IP and interface and the
> > web/mail/... to other IPs and interface.  This can be in 
> > different subnets
> > and different physical switches, hub and routers as well.
> > 
> > Christopher K. Bipes         mailto:ChrisB@Cross-Check.com
> > Sr. Programmer/Analyst       mailto:Chris_Bipes@Yahoo.com
> > CrossCheck, Inc.     http://www.cross-check.com
> > 6119 State Farm Drive        Phone: 707 586-0551 x 1102
> > Rohnert Park CA  94928 Fax: 707 586-1884
> > 
> > If consistency is the hobgoblin of little minds, only 
> > geniuses work here.
> > Karen Herbelin - Readers Digest 3/2000
> > 
> > 
> > -----Original Message-----
> > From: Stone, Brad V (TC) [mailto:bvstone@taylorcorp.com]
> > Sent: Monday, May 08, 2000 8:30 AM
> > To: 'MIDRANGE-L@midrange.com'
> > Subject: one external IP to multiple internal IPs? Ideas?
> > 
> > 
> > I am looking for ideas.
> > 
> > We have an As/400 that we are using for web serving.  Our 
> > network group has
> > a router set up to route requests to it.
> > 
> > This server will be serving multiple companies for customer 
> > service.  What I
> > would like to do ideally is set up an instance for each 
> company (using
> > BindSpecific) so that each of them can run in seperate jobs.  
> > Also, logging
> > seperately is another reason I want to do this.
> > 
> > What we plan on doing is making a subdomain for the companies 
> > that will
> > route these requests to the AS/400.  For example, 
> > company1.com will have a
> > subdomain of cso.company1.com that will be routed a 
> > particular external IP
> > address, then routed to the AS/400.
> > 
> > Our network guys tell me they can only route IPs on a one to 
> > one basis, so
> > to run multiple servers I would need an external IP for 
> each company.
> > 
> > So, here's what I want..
> > 
> > URL                 Ext. IP      AS/400 IP
> > cso.company1.com -> 218.1.1.2 -> 172.25.6.1
> > cso.company2.com -> 218.1.1.2 -> 172.25.6.2
> > etc.. 
> > etc..
> > 
> > Does anyone else have any better ideas?  I know I can use 
> > virtual hosts and
> > one IP address, but like I said, I'd rather keep them seperate.
> > 
> > Brad> 
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