I asked about SMB on Centos 6. shimi answered:
samba-swat is installed, fine, but was the service actually started? You have not shown proof of that
If it does,
netstat -pltn
Will tell you about listening ports (in case you got the networking wrong)
As NMAP already indicated, port 901 is not open. It is not listed in the netstat output, either. But why not?