[CentOS] CentOS 6 and NIS not working

I am having no luck getting NIS to work on a clean install of CentOS 6. It seems to be an issue with ypbind.

I have simple /etc/yp.conf which explicitly sets the server

domain myDomain server myServer

The service seems to start okay

#service ypbind start
Starting NIS service:  [OK]
Binding NIS service: … [OK]

But when I try to use any of the yp services, like ypwhich

#ypwhich
ypwhich: Can't communicate with ypbind

This is usually blamed on ypbind not running, but ypbind is confirmed to be running

#ps -ef | grep ypbind
root		3033	1	0	15:11	?	00:00:00	/usr/sbin/ypbind

ypcat also does not work

#ypcat netgroup
No such map net group. Reason: Can't bind to the server which serves this domain

I have double checked that the server is running

#rpcinfo -u myServer ypserv
program 100004 version 1 ready and waiting
program 100004 version 2 ready and waiting

The domain name seems to be set correctly as well

#domainname
myDomain

I have tried disabling iptables and selinux, but that has no effect. I am probably missing something obvious, but NIS has never given me these issues before.

Any suggestions on what might be the culprit?

Martyn