This article applies to:
- Trustwave MailMarshal (SEG)
Issue:
- The Local User Part of email addresses is limited to 64 characters according to Internet RFC (See RFC 5322, Section 4.5.3.1.1)
- The Domain Part of email addresses is limited to 255 characters according to Internet RFC (See RFC 5322, Section 4.5.3.1.2)
- The entire email address is limited to 254 characters according to Internet RFC
- However, experience shows that a significant number of legitimate messages generated by other software providers violate this standard by setting the local part to more than 64 characters
- MailMarshal does not take any action on non-complying addresses by default.
Enforcing the limit:
- You can enforce the limit at the MailMarshal Receiver using the Registry entry described in this article.
- When enforced, long addresses are rejected at the Receiver with a message: 553 MAIL FROM: mailbox name too long
Note: This setting ENABLES the length check which is DISABLED by default.
- In MailMarshal 10.0 and above, open the Management Console and navigate to Advanced Settings. Add a new value:
- Name: Receiver.EnforceLocalUserLengthCheck
- Type: Boolean
- Value: True (selected)
- In MailMarshal 8.X and below, open the Registry Editor on the Array Manager. Within the base registry key, navigate to \Default\Receiver
- In version 8.X: HKEY_LOCAL_MACHINE\SOFTWARE\Trustwave\Secure Email Gateway\Default\Receiver
- For information about the registry location for each version, see article Q10832.
- Enter the value as a new DWORD value named EnforceLocalUserLengthCheck with value 1 (true).
- Save your registry settings or configuration settings.
- Commit the configuration changes and restart the MailMarshal Receiver service on each node.
As always, take due care when editing the Registry. Trustwave recommends that you make a backup before applying any changes.