554 Your access to this mail system has been rejected due to the sending MTA’s poor reputation

In some situations, emails sent to a particular domain returned a bounced email with subject

Mail delivery failed: returning message to sender

and the body contains this relevant information,

This message was created automatically by mail delivery software. A message that you sent could not be delivered to one or more of its recipients. This is a permanent error. The following address(es) failed:

554 Your access to this mail system has been rejected due to the sending MTA’s poor reputation. If you believe that this failure is in error, please contact the intended recipient via alternate means.

To figure out how to solve this problem I started checking my IP address against a black list checkers services.

whatismyipaddress.com results

 

NHibernate.HibernateException SqlDateTime overflow

Working on a project based on the wonderful Sharp Architecture, I’ve noticed that under some circumstances, creating and saving an instance of an object which has DateTime members raised an exception like this one,

NHibernate.HibernateException SqlDateTime overflow. Must be between 1/1/1753 12:00:00 AM and 12/31/9999 11:59:59 PM.

Here is a sample code, where I just change the customer name.

Let’s suppose I have Customer persistence class, which is defined as,

public class Customer : Entity

{   #region Members

public virtual string Name { get; set; }

public virtual DateTime Birthday { get; set; }

#endregion Members

}

Now, get our first Customer and change his Name,

Customer cust = customerRepository.Get(1);

customerRepository.DbContext.BeginTransaction();

cust.Name = “John”;

customerRepository.SaveOrUpdate(cust);

customerRepository.DbContext.CommitTransaction();

Quick Solution: Change the DateTime fiel to null able adding a ? sign. So, the Birthday declaration should be like this,

public virtual DateTime? Birthday { get; set; }

In order to know the reason of this issue, please refer to this great explanation at http://barchitect.blogspot.com/2009/07/nhibernate-sqldatetime-overflow-issue.html

Laplace transform videos in spanish

An excelent set of videos to undestand Laplace transform

In these videos you can understand the Laplace transform’s definition and its main properties.

http://www.youtube.com/watch?v=wNu80ZvG2JE

http://www.youtube.com/watch?v=p45b0I-7NYA&feature=related

http://www.youtube.com/watch?v=haBLD96vlE8&feature=related

http://www.youtube.com/watch?v=lwyRp2k3JqU&feature=related

http://www.youtube.com/watch?v=lOq5dRDFWNI&feature=related

http://www.youtube.com/watch?v=ykw32ooDhdU&feature=related

Finally, the blog is online

As this is the first post, I’m going to use use this space for a brief introduction about the goals to accomplish with this blog.

Firstly, I’d like to have a central place to write notes regarding some areas of my interest and summaries of my researching tasks.

Also, I’d like to share some ideas mainly as a way to refresh my mind and get your opinions.

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