How to find server root DN?

[Mikael Grehn <mikael@envilogg.se>]

Howdy!

I have written an LDAP klient (v3) that I would like to try against
different servers f.e. "ldap.bigfoot.com" e.t.c. These are (mostly)
LDAPv2 servers that doesnt support DSE (which contain root DN?). The
client works great with my own LDAP server (in which I know the root DN,
"c=SE").

How can I find a server root DN in an LDAPv2 server? What should the
search criteria be to perform such a request(get root dn)?

Should I use the DSE entry in LDAPv3 server to find out the root DN?
What is the attributetype that contain this value?

Any public (anonymous access) LDAPv3 server out there that I could test
against? LDAPv2 servers I know: "ldap.bigfoot.com",
"ldap.infospace.com"," ldap.switchboard.com", "ldap.whowhere.com" e.t.c.
but how should I perform search requests against these when I dont know
the DN schema/root DN?

Greatful for any help/hints!
--
sincerely

Mikael Grehn