Various Types of DNS records

I am somewhat confused on the various types of DNS records. I know about A records, but that's pretty much it. I have a local DNS server on my network, but I know so little I haven't been able to use all its functions (only set some A records)

Can someone please help me understand what on earth an SRV record is? I read about them briefly, and it seems you can point all traffic on a specific domain to an IP AND a specific port, but I could be wrong.

Theoretically is there a way to have all traffic going to exampleserver.mydomain.com go to (mypublicip):25566 even if it came in on 25565?

Thanks

SRV (Service Record) is just a way of defining the location of a server for a specific service. So any traffic that queries the DNS about a particular service will be sent to it. This is for large enterprise where machines querying for example, where a SMTP server is.

Theoretically is there a way to have all traffic going to exampleserver.mydomain.com go to (mypublicip):25566 even if it came in on 25565?

That is just a ranged port forward. Simply expect traffic on (for example) 25560-25570 and redirect to 25565. Having too large a range can play hell with returning traffic getting caught in the range and simply not reaching its destination.

Right but I need traffic coming in on 25565 to go to another server, but if I can make it depend on what domain the client uses (like Apache name hosts) then that gets what I need done

Contrary to what I mostly said in my OP, minecraft now (since 1.7.*) does support the use of SRV records directly. So take a quick look into that.