Another error showed up when i try to get a free .cer from verisign

Question

i used
keytool -genkey -keyalg "RSA"
to generate a pair of keys, and then, used
keytool -certreq
to get the certificate request file, but when i submit the CSR file, an error comes out:
Error - Certificate Signing Request
The Certificate Signing Request (CSR) that you submitted contains characters that are not permited such as `*', `?', `:', or space in Common Name field. The Common Name should be a fully qualified domain name WITHOUT `*', `?', `:', space, "http://", or ":port number". For example, server.verisign.com is a fully qualified domain name. Please create a new CSR with a correct Common Name using your server software and submit the new CSR.
I haved checked my CSR file and didn't find any illigal character mentioned above except in the "begin" and "end" part, and, what does "Common Name field" mean? i just followed the java tutorial to create the keys and the CSR file, and didn't read anything about "Common Name field". i really don't understand what's going on.
thank you in advance for any help.
regards

Answer 1

The Common Name (CN) is a part of the Distinguished Name
Probably you're trying to get a free Web Server certificate. Verisign checks if the CN is a name that can be given to a machine, like www.microsoft.com or java.sun.com. Such check avoids problems when trying to make a SSL connection. You can make a connection to a web server whose certificate reads "CN=login.yahoo.com" but not to a web server whose certificate reads "CN=first machine at garish's site".
If you want to get a free Email certificate you can have names with spaces inside, like "CN=Raghavan Srinivas". If you want to put accented letters inside (like "CN=Java Café" a lot of software has problem with accented letters, so avoid using accented letters in the CN.