Zimbra – Change max attachment size for email

While working with Zimbra, I figured out today that I needed to increase the attachment size limit of the message to send larger messages. The default attachment size limit is 10MB. Even if the attachment is a little less than 10MB, it won’t send quoting the same error that the maximum message size is crossing the limits.

1. Change user:

# su zimbra

2: Check size:

Maximum message Size
# zmprov gacf | grep zimbraMtaMaxMessageSize
zimbraMtaMaxMessageSize: 20480000

File upload size configuration
# zmprov gacf | grep zimbraFileUploadMaxSize
zimbraFileUploadMaxSize: 20480000

The current size is 20MB.

Now, we will change the maximum size.

10240000 = 10mb
20480000 = 20mb
30720000 = 30mb

3. Set new size:

Maximum message Size
# zmprov mcf zimbraMtaMaxMessageSize 30720000

File upload size configuration
# zmprov mcf zimbraFileUploadMaxSize 30720000

Finish, now the Maximum message Size and File upload size is 30MB.

Note: Usually it is not advisable to increase the size of message to very large quantities as it will slow down the server performance