You can fix this by editing exim configuration file.
steps:
1. vi /etc/exim.conf
2. Find the bellow entry
#daemon_smtp_ports = 25 : 587
3. remove the comment
daemon_smtp_ports = 25 : 587
If the port is not mentioned in exim.conf, please add it.
You can recreate qmail’s queue by following the steps given below, but while recreating all the current messages will be removed from the queue and cannot be restored. So it is better to take backup of messages before starting.
Steps:
1. log into server and stop qmail – #/etc/init.d/qmail stop
2. cd /var/qmail/queue
3. rm -rf info intd local mess remote todo
4. mkdir mess
5. for i in `seq 0 22`; do
mkdir -p mess/$i
done
cp -r mess info
cp -r mess intd
cp -r mess local
cp -r mess remote
cp -r mess todo
chmod -R 750 mess todo
chown -R qmailq:qmail mess todo
chmod -R 700 info intd local remote
chown -R qmailq:qmail intd
chown -R qmails:qmail info local remote
6. Now start qmail— /etc/init.d/qmail start
To create email account on an Android Mobile Device, please follow the below steps.
1. From the Home screen, click on the gray Application button.
2. Click on Email.
3. Then Next.
4. Using the keyboard, enter:
Email Address
Your full email address
Password
Your email password
5. click Next.
6. Click IMAP Account or POP Account.
7. Enter the following:
Username
Your full email address
Password
Your email password
IMAP/POP Server
Your Incoming POP or IMAP Server
(Optional) Security type
SSL (Accept all certificates)
IMAP/POP path prefix
No changes required
Incoming port
IMAP without SSL –143
IMAP with SSL –993
POP without SSL –110
POP with SSL –995
8. Tap Next.
9. In Outgoing server settings type:
Server name
Your Outgoing SMTP Server
(Optional)Security type
SSL (Accept all certificates)
Outgoing port
Without SSL – one of the following:25, 80, 3535, 587
With SSL –465
Require sign-in
Select to enable
Username
Your full email address
Password
Your email password
10. click Next.
11. Choose desired Account Settings.
12. Choose desired additional settings on Set up email.
13. Click on Done.

You can use the command given below to check the hard disk performance.
hdparm /dev/sda
/dev/sda:
IO_support = 0 (default 16-bit)
readonly = 0 (off)
readahead = 256 (on)
geometry = 30401/255/63, sectors = 488397168, start = 0
1. Installing ext3grep…
wget http://ext3grep.googlecode.com/files/ext3grep-0.7.0.tar.gz
tar -xvzf ext3grep-0.7.0.tar.gz
cd ext3grep
./configure
make
(more…)