Friday, October 30, 2009

DKIM to help fight SPAM

Have you ever heard of DKIM? duh, DKIM what's this?

DomainKeys Identified Mail (DKIM) lets an organization take responsibility for a message while it is in transit. The organization is a handler of the message, either as its originator or as an intermediary. Their reputation is the basis for evaluating whether to trust the message for delivery. Technically DKIM provides a method for validating a domain name identity that is associated with a message through cryptographic authentication

It's similar to SPF (Sender Policy Framwork)
SPF works by having domains publish reverse MX records to display which machines are designated as mail sending machines for that domain. When receiving a message from a domain, the recipient can check those records to make sure mail is coming from a designated sending machine.

DomainKeys (DKIM) enables a sending domain to cryptographically sign outgoing messages, allowing the sending domain to assert responsibility for a message. When receiving a message from a domain, the recipient can check the signature of the message to verify that the message is, indeed, from the sending domain and that the message has not been tampered with.
It seems to help for the SMTP weakness exploited by spammers

An SMTP mail has at least two parts, the envelope and the content. The envelope defines from whom the mail is coming and to whom it should be delivered. In the content is defined what sender and recipient should be shown in the mail client (doesn't matter what kind of mail client you use).

Usually both entries are the same. Spammers however abuse this weakness by entering real recipient addresses only in the envelope, whereas the content has completely different entries. Domino (as every other mail system) uses the envelope information to route the emails. Unfortunately the envelope information is deleted by the router as soon as the email has left the The result is, that the recipient gets an email without beeing listed in any field (To, Copy or Blindcopy). This behaviour is according to the RFC standard of SMTP, because otherwise no blindcopy functionality will be possible.

Do you use it?Do you see performance impacts?

We currently use Barracuda, we can enable it but from the documentation it seems that it could be have perfomance impacts.

Tuesday, October 27, 2009

Microsoft - Roadmap for Outlook Personal Folders (.pst) Documentation

In order to facilitate interoperability and enable customers and vendors to access the data in .pst files on a variety of platforms, we will be releasing documentation for the .pst file format. This will allow developers to read, create, and interoperate with the data in .pst files in server and client scenarios using the programming language and platform of their choice. The technical documentation will detail how the data is stored, along with guidance for accessing that data from other software applications. It also will highlight the structure of the .pst file, provide details like how to navigate the folder hierarchy, and explain how to access the individual data objects and properties.


From ZDNet

Thursday, October 15, 2009

What notes.ini variables have become obsolete in Notes/Domino 8.x?

What notes.ini file variables are now obsolete in Notes/Domino 8.x?


Domino Server 8.5.x group cache performance issue based on workload

You may experience performance issues (not hangs) on Domino Release 8.5.x. The performance may appear to be degrading based on workload. This issue is most likely exposed on servers that make use of user authentication for example like mail servers or web servers. The issue is related to the Domino group cache code for authentication.