[CentOS] how to tst my backup mail server

Dear ALl,

Sorry for my posting here but do apprecite if u guys help me..

I have already CenOS 5 and been used as my Primary DNS and primary sendmail mail server and is working perfectly fine

i also have another Centos MAchine being used as my secondary DNS server and been workin fine..

i want to use this machine as my backup mail server and has gone to the DOCS have configured DNS and sendmail for a backup mail server.

but i really dont know how i would test if my secondary mail server is workin

apprecite if you cd have some examples or steps to check my newly setup backup mail server

Thanks and Regards

simon