When a VNX 5300 is first configured, one of the setting is the SMTP server to use for sending out emails as part of the systems call home configuration.   Here are the steps to reconfigure that SMTP setting should you need to.
The command to configure the call home settings is “/nas/sbin/nas_connecthome”.
To run the command you need to ssh into the VNX control station with the nasadmin user.  Once logged in, become root by using the su command (no dash).
Usage summary

/nas/sbin/nas_connecthome
usage: nas_connecthome
-info
| -test { -email_1 | -email_2 | -ftp_1 | -ftp_2 | -modem_1 | -modem_2 | -https }
| -modify [ -modem_priority {Disabled | 1 | 2 | 3} ]
[ -modem_number <phone_number> ]
[ -modem_number_2 <phone_number> ]
[ -ftp_priority {Disabled | 1 | 2 | 3} ]
[ -ftp_server {  | <ip_addr>} ]
[ -ftp_port  ]
[ -ftp_ipprotocol { IPv4 | IPv6 } ]
[ -ftp_user  ]
[ -ftp_passwd [passwd] ]
[ -ftp_folder  ]
[ -ftp_mode {active | passive} ]
[ -ftp_server_2 {  | <ip_addr>} ]
[ -ftp_port_2  ]
[ -ftp_ipprotocol_2 { IPv4 | IPv6 } ]
[ -ftp_user_2  ]
[ -ftp_passwd_2 [passwd] ]
[ -ftp_folder_2  ]
[ -ftp_mode_2 {active | passive} ]
[ -email_priority {Disabled | 1 | 2 | 3} ]
[ -email_from <email_addr> ]
[ -email_to {<email_addr>[,<email_addr>]} ]
[ -email_subject <email_subject> ]
[ -email_server {  | <ip_addr>} ]
[ -email_ipprotocol { IPv4 | IPv6 } ]
[ -email_server_2 {  | <ip_addr>} ]
[ -email_ipprotocol_2 { IPv4 | IPv6 } ]
[ -https_priority {Disabled | 1 | 2 | 3} ]
[ -https_url { url }
[ -https_ipprotocol { IPv4 | IPv6 } ]
[ -https_ca_file { ca_certificate_file_name } ]
[ -https_verify_server { yes | no } ]
[ -dial_in_number <phone_number> ]
[ -serial_number <serial_number> ]
[ -site_id <site_id> ]
[ -encryption_enabled { yes | no } ]
[ -dial_in_enabled { yes | no } ]
[ -service_info ]
| -help

 
Retrieving the current configuration
/nas/sbin/nas_connecthome -info
Changing the outgoing smtp server
/nas/sbin/nas_connecthome -modify -email_server 192.168.0.1
Send a test email
/nas/sbin/nas_connecthome -test -email_1