IP Migration questions

[stratagem]

I have a server configured with multiple IPs. All of the IPs must be changed.

I've added the new IPs to the network configuration, changed the gateway and host, updated the main shared IP setting in the WHM, added the new IPs to the address pool, and changed the nameserver entries. So far, so good.

Now, I have to begin migrating accounts. I will be using the IP migration wizard for the first time.

1. I seem to remember an issue with the default site on a shared IP. That is, the first site placed on the IP would be the one that shows up when a request is made without a virtual domain specified. If so, how do I pick the site if I'm using the IP migration wizard? Do I change the selected account IP beforehand?
2. I've seen some mention of not using the main IP as the shared IP. Any details or links to the rationale?
3. The wizard configures each site for simultaneous access on the old and new IPs to smooth transition. Once DNS changes have propagated, the old IP settings are removed. Do I enter the wizard twice, or do I leave a browser window open for a day while waiting?

Just trying to minimize any suprises on my first time through.

[chirpy]

1. It's simply the first virtualhost in /usr/local/apache/conf/httpd.conf that uses a given IP address that will be displayed if someone browses to that IP address. You can rearrange the VirtualHost containers to suit your needs

2. Not true. You can use the main IP address as the shared IP address if you wish. There's no point in using IP addresses unless it's a requirement (e.g. for SSL cert sites).

3. Where did you get that from? AFAIK, it simply switches the virtualhosts directly from the old to the new IP addresses and updates the DNS zones immediately.

[stratagem]

1. Thank you.
2. That's how I look at it. I was curious and looking for details.
3. The server is leased. The company now has a consolidated block with ARIN and they made some instructions available. I've never used the IP Migration Wizard before and I'm trying to get a feel for the steps involved. Thanks for the info.

...and updates the DNS zones immediately.

Perhaps the next step removes the old IPs from the pool/completely and I misunderstood those instructions?
Both sets of IPs are active on the server. The instructions implied that virtual host requests using stale DNS info would be serviced after seeing "DNS migration has been completed on this server". Then, after propagation, "Clicking here" to finish the migration and remove the "specal configuration" (yeah, I know, clear as mud).