Wednesday, June 20, 2012

how to use VirtualBox's "internal network" mode

  • VirtualBox 4.1.16 r78094
  • OS: Debian Linux
There is a situation when your Guest OSs need to access the Internet via NAT, for example, when you are using a dorm's Internet which they allow only 1 machine per account. And you also need your guest OSs to communicate with each other.
Let's say there are 2 Guest OSs which have to connect to the Internet via NAT. And you also need both of them to communicate with each other. This is impossible if you use just NAT one each virtual machine as they can't reach each other. You have to use VirtualBox's internal network.
This is the TRICKY part.

You must have 2 network interfaces on each virtual machine.

One is set to use NAT, another one is set to use "internal network" (choose "intnet1"). Then run this command:

VBoxManage dhcpserver add --netname intnet1
VBoxManage dhcpserver modify --netname intnet1 --ip --netmask --lowerip --upperip --enable


bandwidthd is a network monitoring tool:

Its unit is Byte on the table and Bit Per Second on the graph.

Tuesday, June 19, 2012

cannot send email from hotmail to google app email

Email contains error messages got from hotmail:

Date: Fri, 15 Jun 2012 20:39:46 -0700
Subject: Delivery Status Notification (Failure)

This is an automatically generated Delivery Status Notification.

Delivery to the following recipients failed.


Reporting-MTA: dns;
Received-From-MTA: dns;COL107-W41
Arrival-Date: Fri, 15 Jun 2012 20:39:36 -0700

Final-Recipient: rfc822;xxx@yyy.zzz
Action: failed
Status: 5.7.1
Diagnostic-Code: smtp;554 5.7.1 <xxx@yyy.zzz>: Relay access denied

It is because hotmail server tries to send email through yyy.zzz server which is not the email server (google's). Actually, hotmail should find address of email server by asking for MX record from the domain yyy.zzz instead.!category-topic/apps/mail-settings/Yd0JG0jRn7M