North American Network Operators Group

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Re: intranet

  • From: Vince Fuller
  • Date: Thu Aug 20 11:04:57 1998

> At 05:43 PM 8/18/98 +0800, [email protected] wrote:
> >Proposed Solution:
> >
> >The 7010 router will be connected to the 2 ISPs.  The 7010 will be upgraded
> >to an IOS that supports NAT; all IP address behind the 7010 will be treated
> >as internal IP addresses (to reduce reconfiguration).  IP address subnets
> >from both ISPs will be NAT-mapped to internal IP addresses over the 7010,
> >including the DNS server and the mail server.
> >
> >The DNS will be configured to use their DNS as the primary name server.
> >The 2 ISPs' name servers will be used as secondary name servers.
> >
> >The mail server will be configured to have 2 IP address, one actual and one
> >virtual IP address using the network card.  The DNS will have an MX 10 and
> >an MX 20, each pointing to one IP addresses for the network card.
> >
> >
> >Is this solution possible?  Will it work?  Did I forget anything?  Any tips?
> That is one way to do it .. another and I think a BETTER way would be to
> only use 1 set of ip's ( a set that is "portable" ) and talk bgp with both
> providers. This way you can move the traffic in the most efficient way . If
> you take routes from both of em you may get a better path to site X from
> provider a and a better path to site Y from provider B . 
> This way if provider a goes down the BGP will move trafic of the link that
> is still  "GOOD" 

The NAT approach has the obvious advantage of being more "CIDR-friendly"
to the "global Internet". It is probably somewhat more complicated, but if
implemented correctly, it should provide reasonable redundancy and load-
sharing just like a "portable" address space solution.