That's dependent on a number of things.

First, do you have one or two SharePoint Farms? (ie. One inside  and one
outside)

Second, what are you using for load  balancing on the outside servers?
(Windows Load balancing or some form of Hardware load balancing)

Third, are all the servers  in the same AD domain?

> First, do you have one or two SharePoint Farms? (ie. One inside  and
one
> outside)

1 farm. All servers  will have and mirror the same content on the two
portals/webapps

> Second, what are you using for load  balancing on the outside servers?
> (Windows Load balancing or some form of Hardware load balancing)

Well...they're not sure yet. They think we're going to use Windows Load
Balancing, but, barring that, they'll go with NetScaler hardware (what
we currently use on our web  servers). What's the major difference
between the two in terms of extending  a web app?

> Third, are all the servers in the same AD domain?

No. Internal servers are on our internal domain, external on the DMZ
somain.

DB is behind the firewall, if that matters, with one way trust on the
outside servers.

The internal server  is mainly our 'failsafe' to allow site admins the
ability to look up and add site users via AD's address book (something
we nor Microsoft could get working on our WSS2 install). Since we had
it, we also made that server the Central admin  box.

At the risk of being annoying I thought  I'd 'bump' this once.

I have a hunch I'm missing the obvious and--it being so obvious--just
isn't mentioned much.

To recap (as briefly as I can):

We have 4 servers  on our farm. One FE inside  our FW, 3 outside (2 FEs,
one App/Search). All 4 servers will have the exact same content. This is
all one farm. It's on two AD domains  (our internal AD and out external
DMZ AD). The DB server  is on our internal AD Domain behind the FW with
one way trust set up.

I will have two portal/web apps  created on the 'inside' server. I now
need to extend these to the outside servers. This internal server is
also running the central  admin app.

I'm stuck on what I need to set up in terms of domain names.

The internal server's apps will be accessed via two domains
(internal1.ourdomain.com and internal2.ourdomain.com)

The external servers will be load  balanced with NetScaler, and will also
have two urls (exernal1.ourdomain.com and external2.ourdomain.com)

What I'm not so sure about is the search/app server. Does that get load
balanced? Do I even need to extend the sites to that server? Does that
server need its own URLs?

OK, I'll take a stab at how to do this. However, your details don't
match up to your description.

All that should be necessary if it's a single Farm would be to extend
the existing Web Applications using Central Admin, but supply an address
that is part of the external domain. The problem is that you say you
have two domains, but the internal is called 'ourdomain.com' and the
external is also called 'ourdomain.com'. I'm not sure how this will
work if the domains  are actually named exactly the same. The search/app
server can't be load  balanced given what you've described (I assume this
is actually the Index server  and not a Query server) because there is
only one. When extending  the existing WebApp you will need to make sure
that the LoadBalanced URL matches the Quorum address of the Load
Balanced Web App. What this is will depend on the Load Balancing system
you are using.

> that is part of the external domain. The problem is that you say you
> have two domains, but the internal is called 'ourdomain.com' and the
> external is also called 'ourdomain.com'. I'm not sure how this will
> work if the domains  are actually named exactly the same.

That's just the TLD. They'd have unique subdomains.

So, we have out extranet and our collaboration portal:

Extranet.ourdomain.com
Teamsites.ourdomain.com

Then there is the internal box, which would likely only be used by
Admins. We'd need to give that unique domain names as it's on a
different network, correct?

> you will need to make sure
> that the LoadBalanced URL matches the Quorum address of the Load
> Balanced Web App.

I'm not familiar with the term 'Quorum address'. I'll look into that.

Quorum address is just the shared address that a client would navigate
to for the Load balancing server  to distribute between different
servers.

Also, if the external has unique subdomains then the full address for
the external webapp should include the subdomain. For example
'Extranet.subdomain.ourdomain.com. Extranet and Teamsites is the name
of the website/server, not the subdomain.