Email Basic Guide

Quick Summary

Email quota per account
  • 100 GB for staff  (Exchange Online)
  • 10 GB for project account (on-premises Exchange 2019)
  • 50 GB for students and alumni (@Connect)

NB: Quota includes inbox and all other mail folders. Check your mailbox usage regularly

If quota reached
  • Staff  (Exchange Online):
    For Staff users, you can email to cchelp@ust.hk to turn on Online Archive Mailbox after reached 90GB.
    1. Warning issued at 98 GB
    2. Cannot send at 99 GB
    3. Cannot send/receive at 100GB
  • Project account (on-premises Exchange 2019):
    1. Warning issued when usage exceeds 95% of quota
    2. Cannot send/receive mail when mailbox is 100% full, with senders receiving a bounce back message
  • Student and Alumni (@Connect):
    1. Warning issued at 49 GB
    2. Cannot send at 49.5 GB
    3. Cannot send/receive at 50GB

NB: Keep monitoring your usage to avoid late delivery of incoming email, and archive older or less frequently used mail.

Maximum size of outgoing message
  • 10 MB for mailing lists
  • 35 MB for students
  • 50 MB (server: smtp.ust.hk)
  • 100 MB among staff users
Maximum number of recipients per outgoing message
  • 500 email addresses (Office 365 users) 1
  • ~250 – 260 (Outlook Client)
  • 300 email addresses (server: smtp.ust.hk)

NB: To email larger numbers of recipients, use the mailing list service.