Status: 5.2.3 (user limit of 1000 kilobytes on message size exceeded)

As you know by now, our company provides Corporate Email Hosting (OpenMail.SG) running on Sun Java System Messaging Server.

Today, one of our clients received this error:

   Status: 5.2.3 (user limit of 1000 kilobytes on message size exceeded)

This is actually one of the feature we set on the MTAs to restrict emails with huge attachments from reaching our clients' mailboxes, thus preventing their email accounts from hitting over-quota limit easily.

It's fairly easy for us to change this limit per system-wide, per domain or even per user level. For this particular client, his company's policy was to restrict emails larger than 1 MB.

To resolve this issue on Sun Java System Messaging Server, we can modify the attribute MsgMaxBlocks in his LDAP profile.

bash-3.00# ldapsearch -D "cn=Directory Manager" -w 12345 -b o=hisdomain.sg,o=isp uid=his.uid mailMsgMaxBlocks

version: 1

dn: uid=his.uid,ou=People,o=hisdomain.sg,o=isp

mailMsgMaxBlocks: 1000

bash-3.00# ldapmodify -D "cn=Directory Manager" -w 12345 

dn: uid=his.uid,ou=People,o=hisdomain.sg,o=isp

changetype: modify

replace: mailMsgMaxBlocks 

mailMsgMaxBlocks: 5000

Note: Messaging Server has a LDAP cache, so any user LDAP modifications may take up to 15 minutes (by default) to take effect. Restart the MTA to flush the cache (./imsimta restart) if you want immediate effect, which I do not recommend.