I've got a site that I've been developing for some time that I just switched over to using private nameservers. While using my host's nameservers Multisites worked fine - now that I've switched none of my Multisites are working at all. The nameservers are set up properly - the master site (which is also the nameserver) works fine, as do several other sites on the host using the new nameservers.

Any reason why switching this would suddenly break multisites?

The master domain (and nameserver) is myathleticresume.com. Slave sites that I have set up to test are slave1.myathleticresume.com and myacademicresume.com.

What do you mean by switch the name server.
A name server is the service that is runing on a server and that is in charge to manage the domain name and publish the Domain Name Server (DNS) information and this is not related to the hosting of a website (HTTP Server).

When you query a Name Server using a domain name, the name server is reponsible to provide the IP address of the server where is located the service required (here the HTTP service).

So this is totally different.

If you mean by change of name server that you have renamed your domain of your master and perhaps the domains present in the slave site, this is something else.
The question in this case is to know if you shared the websites and in particular shared the users between the website.

If the domain names are not changed, verify that the Name Server return the same IP address that you did before or that it correspond to the new IP address where is located your server.
You can test such reply with a DOS command like "nslookup www.domain.com" and this will return the IP address of the domain.

In this case the DNS server is my master website. So let's take three example sites that I'm working with. These are all valid domain names so you can test them.

www.myathleticresume.com is the master website with MultiSites installed. I've set this site up as a name server with my registrar (ns1.myathleticresume.com, ns2.myathleticresume.com) rather than using my host's default nameserver, in the hope that I would be able to avoid setting up domain aliases for each multisites site. The name servers for this site are set to itself (ns1.myathleticresume.com, ns2.myathleticresume.com), and work properly. nslookup on this domain returns the correct IP.

slave1.myathleticresume.com is a multisites client site. Since it's a subdomain of the master site, I would expect it to work without a problem, but nslookup returns "server can't find.... :REFUSED"

www.myacademicresume.com is another multisites client site. It's name servers (at GoDaddy) are set to the master: ns1.myathleticresume.com, ns2.myathleticresume.com. The nslookup on this site returns the same error as the subdomain above.

www.juangamboa.com is another site on the same server, but it's a separate install, not a multisites client. It's name servers are set to ns1.myathleticresume.com and ns2.myathleticresume.com. nslookup returns the correct IP and the site works properly.

So why don't the multisites clients work? I could understand if the external domain (myacademicresume.com) didn't work, but the fact that subdomains don't work either makes me think there's something else going on here.

This is a linux server running plesk.

One other thought - could turning on the "named" service cause this problem?

Does your IP address is 205.186.136.207 ?
The IP corresponding to the www.myathleticresume.com is returned as 205.186.136.207 and your name server has the address 205.186.136.207 and 205.186.136.207.

If your IP is correct you have to check that your HTTP Server receive correctly the packets.

Put any text files with a unique name to ensure that your HTTP Server is correctly configure.
This will help you test the configuration of your server (without Joomla and of course without JMS Multisites).

If you want that we help you check the configuration of your server, this is possible with our billable support that you can order at
www.jms2win.com/download?page=shop.produ...35&category_id=1

Your problem see related to the configuration of your server that does not reach the HTTP Server

If you have a connection refused to access your name server, this may explain why you don't have access to your HTTP Server.

If you are using Plesk, you perhaps have to check the Plesk configuration.
They add plenty of security that may explain why this does not work anymore and I don't see any reason why the document root of the domain is refused.

Perhaps you should contact the support of the company that provide you the server to ask them how to configure your server

I'm pretty sure the server is configured correctly. The IPs are correct, and the master domain (myathleticresume.com) is working properly. Additionally I can get to the multisites slave sites by going to www.myathleticresume.com/multisites/slave1 or www.myathleticresume.com/multisites/myacademicresume.com. So the http service is working properly, multisites is just not intercepting and redirecting the requests for slave sites.