Unable to send email from host machine to custom email address

dissertation writing assistance where to start I have my own personalised email address which is powered by Google Apps: ericlin at ericlin dot me. I have been receiving emails fine for many years without issues. However, since I setup my own blog server a few year ago, I had never be able to receive any email sent from my host machine via postfix.

http://www.hotelsb.eu/homework-help-government-sites/ I have tried many tests:

go to site – email from cron job
– email from command line using “sendmail”
– email from wordpress

http://perfectperceptionmedia.com/custom-essays-for-cheap/ None of them were working. However, if I use normal gmail or ymail address, they all reached destination without issues.

http://www.pessebremoviment.com/buy-btec-coursework/ buy btec coursework The following were what was logged on my server under /var/log/syslog:

follow url Jun 10 02:45:04 ericlin postfix/cleanup[12369]: 2601D43AC3: message-id=<0f5e23cef7e94f466eed4183e17476b0@www.ericlin.me> Jun 10 02:45:04 ericlin postfix/qmgr[30415]: 2601D43AC3: from=<www-data@ericlin.me>, size=701, nrcpt=1 (queue active) Jun 10 02:45:04 ericlin postfix/local[12375]: 2601D43AC3: to=<ericlin at ericlin dot me>, relay=local, delay=0.01, delays=0.01/0/0/0, dsn=2.0.0, status=sent (delivered to mailbox) Jun 10 02:45:04 ericlin postfix/qmgr[30415]: 2601D43AC3: removed

http://serc.eng.usm.my/?nursing-papers-online the logs for working email was following:

business planning services Jun 10 03:09:07 ericlin postfix/cleanup[12672]: DED8843AC4: message-id=<ed4e377a0fd860e76a4853ae3063452b@www.ericlin.me> Jun 10 03:09:07 ericlin postfix/qmgr[12614]: DED8843AC4: from=<www-data@ericlin.me>, size=5170, nrcpt=1 (queue active) Jun 10 03:09:08 ericlin postfix/smtp[12674]: DED8843AC4: to=<someemail@gmail.com>, relay=smtp.gmail.com[]:587, delay=0.74, delays=0.02/0.01/0.2/0.51, dsn=2.0.0, status=sent (250 2.0.0 OK 1465528180 18sm2559005qkd.30 - gsmtp) Jun 10 03:09:08 ericlin postfix/qmgr[12614]: DED8843AC4: removed

http://bsqmgroup.com/?p=nazi-writing You can see the differences between the two logs were the final message after status=sent, successful one was http://lacesoflove.org/?p=wordpress-thesis-custom-body (250 2.0.0 OK 1465528180 18sm2559005qkd.30 – gsmtp), however, failed one was can pay someone do my paper (delivered to mailbox)

enter I had been searching for a solution for a long time, but never be able to find a fix.

college essays inspiration Today I spent another few hours trying to dig out if I can find anything, finally it is fixed.

http://envsci.uprrp.edu/?dissertation-helper-2d The problem is the following line in the postfix’s configuration file /etc/postfix/main.cf, there is a line like below

http://www.callforassistance.com/?online-dissertation-writing-service online dissertation writing service mydestination = ericlin.me, ip-172-31-50-123.ec2.internal, localhost.ec2.internal, localhost

master thesis augmented reality The problem is that I added my own domain (ericlin.me) to the list, which was wrong. After removing it, issue resolved!! ^_^.

I hope this can help someone with similar problems.

How to SSH into Centos in VirtualBox

Today I created a CentOS virtual machine in VirtualBox on my Mac for testing Hadoop purpose, however, I was not able to SSH into the newly created virtual machine, and SSH command returned timeout error:

$ ssh root@
ssh: connect to host port 22: Operation timed out

The output of “ip addr show” in the CentOS:


To fix the issue, I did the following:

1. Go to Devices > Network > Network Settings
2. Click on “Port Forwarding”
3. Then enter the details similar as below:


I did not need to restart the VM, and I just ran the following SSH command from host, and issue resolved:

$ ssh -p 2222 root@
The authenticity of host '[]:2222 ([]:2222)' can't be established.
ECDSA key fingerprint is SHA256:QWANQHt0hrV+l98si9RT1u5r0H9Q6A/GCe5jR+MQbHs.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '[]:2222' (ECDSA) to the list of known hosts.
root@'s password:
Last failed login: Wed May 25 15:26:45 AEST 2016 from on ssh:notty
There was 1 failed login attempt since the last successful login.
Last login: Wed May 25 15:22:16 2016 from localhost

Debugging PHP-App Hosted in VirturalBox CentOS VM Using Netbeans

Setting up debugging locally on one machine (both Netbeans and xdebug on the same host) is easy enough. However, if you want to connect Netbeans to a xdebug over to a guest virtual machine, it will require a bit of work, but not hard.

My host machine is Windows 7 and running a CentOS virtual machine inside VirtualBox. The following was what I did to get it running.

Firstly I installed C and C++ compilers, which comes in the “Development Tools”

$ sudo yum groupinstall 'Development Tools'

then I installed php-devel which would give me phpize (which is required by pecl when installing xdebug)

$ sudo yum install php-devel

Now I was ready to install xdebug:

$ sudo pecl install xdebug

Once that was done, I updated php.ini file to enable xdebug. Find the xdebug section in php.ini file, if no, create one section for it under /etc/php.ini



xdebug.remote_enable  = On
xdebug.remote_host    =
xdebug.remote_port    = 9000
xdebug.remote_handler = dbgp
xdebug.remote_mode    = req

xdebug.remote_connect_back = On
xdebug.idekey = "netbeans-xdebug"
xdebug.remote_log = /tmp/xdebug.log

You will need to find the path to xdebug.so file by running:

find / -name xdebug.so

Yours might be different from mine.

Now I was ready to enable xdebug in Netbeans, which was running on the host machine (Windows 7 in my case). Under Tools > Options > PHP > Debugging:

Debugger Port: 9000
Session ID: netbeans-xdebug

Under Project Properties (right click on project root in the Project window) > Run Configuration:

Run as: Local Web Site (running on local web server)
Project URL: http://localhost:8080/ Index file: index.php

(I have setup port forwarding from 8080 on my localhost to port 80 on my virtual machine)

Under Project Properties > Run Configuration > Advanced

Debug URL: Default: http://localhost:8080/index.php
Path Mapping:
Server Path: /path/to/project/in/guest
Project Path: /path/to/project/in/host/

That’s it, now I am able to start setting break points and press Ctrl + F5 to start debugging in Netbeans over the virtual machine.

Enabling mcrypt for php >= 5.4 in Ubuntu 13.10

Ubuntu 13.10 (Saucy) comes with PHP 5.5.3 and does not enable mcrypt by default. I am currently working on a personal project that requires to use mcrypt to encrypt and decrypt data. So I will need to enable it manually.

To enable mcrypt is easy, simply following the steps below:

$ sudo mv /etc/php5/conf.d/mcrypt.ini /etc/php5/mods-available/
$ sudo php5enmod mcrypt
$ sudo service apache2 restart

What “php5enmod” does is simply enabling a PHP5 module by creating a symbolic link from conf.d directory to the real config file under “mods-available”.

So, after we run “php5enmod mcrypt” command, the following files will be created:


which are symlinks to


The prefix “20” is the priority of module, and the default is 20 when you run “php5enmod” command.

If you don’t need the mcrypt module for the command line, you can simply remove the symlink under /etc/php5/cli/20-mcrypt.ini.

Hope this helps.

Installing Single Node Hadoop 2.4 on CentOS 6.3

There are lots of options you can go to install Hadoop, and Cloudera is one of the easiest. However, if you just want to experience Hadoop on a virtual machine, having Cloudera on top will eat lots of your memory. It would be much better to just install vanilla Hadoop from its official website.

This post will focus on getting Hadoop running on CentOS without any third party software.

link Configure “hadoop”user

The following steps assumes that you logged in as “root” user.

[root@hadoop-spark-vm root]$ adduser hadoop

This should add a new user with username “hadoop” and a group called “hadoop”

Update “hadopp”‘s password:

[root@hadoop-spark-vm root]$ passwd hadoop

Give “hadoop” user “sudo” access, open ‘/etc/sudoers’ and add the following line:

hadoop ALL=(ALL) ALL

And now login as “hadoop” user:

[root@hadoop-spark-vm root]$ su - hadoop

http://kofc2204.net/?p=free-poultry-farming-business-plan Set up the “passwordless” SSH

Run the following commands:

[hadoop@hadoop-spark-vm hadoop]$ ssh-keygen -t rsa -P ''
[hadoop@hadoop-spark-vm hadoop]$ sudo cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys

Install JAVA

[hadoop@hadoop-spark-vm hadoop]$ sudo yum install java-1.7.0-openjdk*

After the installation, verify JAVA:

[hadoop@hadoop-spark-vm hadoop]$ java -version
java version "1.7.0_55"
OpenJDK Runtime Environment (rhel- u55-b13)
OpenJDK 64-Bit Server VM (build 24.51-b03, mixed mode)

The folder /etc/alternatives contains a link to JAVA installation:

[hadoop@hadoop-spark-vm hadoop]$ ll /etc/alternatives/java
lrwxrwxrwx 1 root root 46 May 21 12:06 /etc/alternatives/java -> /usr/lib/jvm/jre-1.7.0-openjdk.x86_64/bin/java

Add the path to JAVA_HOME environment variable by updating ~/.bashrc

export JAVA_HOME=/usr/lib/jvm/jre-1.7.0-openjdk.x86_64/bin/java

watch Now we are ready to install Hadoop

Download Hadoop’s binary package:

[hadoop@hadoop-spark-vm hadoop]$ cd ~
[hadoop@hadoop-spark-vm hadoop]$ wget http://apache.mirror.uber.com.au/hadoop/common/current/hadoop-2.4.0.tar.gz # download
[hadoop@hadoop-spark-vm hadoop]$ tar xzvf hadoop-2.4.0.tar.gz # un-tar the archive
[hadoop@hadoop-spark-vm hadoop]$ sudo mv hadoop-2.4.0 /usr/local/hadoop # move un-tar-ed directory to /usr/local/hadoop
[hadoop@hadoop-spark-vm hadoop]$ sudo chown -R hadoop:hadoop /usr/local/hadoop # change the ownership of /usr/local/hadoop to "hadoop" user and group

Next create namenode and datanode folders:

[hadoop@hadoop-spark-vm hadoop]$ mkdir -p ~/hadoopspace/hdfs/namenode
[hadoop@hadoop-spark-vm hadoop]$ mkdir -p ~/hadoopspace/hdfs/datanode

Configuring Hadoop

Add the following lines into ~/.bashrc to setup environment variable for Hadoop:

export HADOOP_INSTALL=/usr/local/hadoop

Update the environment variable immedicately:

[hadoop@hadoop-spark-vm hadoop]$ source ~/.bashrc

Go to “/usr/local/hadoop/etc/hadoop/” directory and update the XML files one by one:


[hadoop@hadoop-spark-vm hadoop]$ cp mapred-site.xml.template mapred-site.xml
[hadoop@hadoop-spark-vm hadoop]$ vi mapred-site.xml

And add the following between the configuration tabs:



Add the following between the configuration tabs:



Add the following between the confiugration tabs:







Add an entry for JAVA_HOME

export JAVA_HOME=/usr/lib/jvm/jre-1.7.0-openjdk.x86_64/

Next, run the following command one by one

hdfs namenode -format

You will see the following outputs:

[hadoop@hadoop-spark-vm hadoop]$ hdfs namenode -format
14/05/21 12:33:50 INFO namenode.NameNode: STARTUP_MSG:
STARTUP_MSG: Starting NameNode
STARTUP_MSG: host = hadoop-spark-vm/
STARTUP_MSG: args = [-format]
STARTUP_MSG: version = 2.4.0
STARTUP_MSG: classpath = /usr/local/hadoop/etc/hadoop:/usr/local/hadoop/share/hadoop/common/lib/zookeeper-3.4.5.jar:/usr/local/hadoop/share/hadoop/common/lib/stax-api-1.0-2.jar:/usr/local/hadoop/share/hadoop/common/lib/commons-beanutils-1.7.0.jar:/usr/local/hadoop/share/hadoop/common/lib/jettison-1.1.jar:/usr/local/hadoop/share/hadoop/common/lib/commons-httpclient-3.1.jar:/usr/local/hadoop/share/hadoop/common/lib/commons-cli-1.2.jar:/usr/local/hadoop/share/hadoop/common/lib/servlet-api-2.5.jar:/usr/local/hadoop/share/hadoop/common/lib/jackson-jaxrs-1.8.8.jar:/usr/local/hadoop/share/hadoop/common/lib/java-xmlbuilder-0.4.jar:/usr/local/hadoop/share/hadoop/common/lib/jasper-runtime-5.5.23.jar:/usr/local/hadoop/share/hadoop/common/lib/jackson-mapper-asl-1.8.8.jar:/usr/local/hadoop/share/hadoop/common/lib/httpclient-4.2.5.jar:/usr/local/hadoop/share/hadoop/common/lib/mockito-all-1.8.5.jar:/usr/local/hadoop/share/hadoop/common/lib/slf4j-log4j12-1.7.5.jar:/usr/local/hadoop/share/hadoop/common/lib/commons-logging-1.1.3.jar:/usr/local/hadoop/share/hadoop/common/lib/jaxb-impl-2.2.3-1.jar:/usr/local/hadoop/share/hadoop/common/lib/paranamer-2.3.jar:/usr/local/hadoop/share/hadoop/common/lib/hadoop-auth-2.4.0.jar:/usr/local/hadoop/share/hadoop/common/lib/jetty-6.1.26.jar:/usr/local/hadoop/share/hadoop/common/lib/jaxb-api-2.2.2.jar:/usr/local/hadoop/share/hadoop/common/lib/jsr305-1.3.9.jar:/usr/local/hadoop/share/hadoop/common/lib/commons-net-3.1.jar:/usr/local/hadoop/share/hadoop/common/lib/slf4j-api-1.7.5.jar:/usr/local/hadoop/share/hadoop/common/lib/commons-codec-1.4.jar:/usr/local/hadoop/share/hadoop/common/lib/commons-compress-1.4.1.jar:/usr/local/hadoop/share/hadoop/common/lib/avro-1.7.4.jar:/usr/local/hadoop/share/hadoop/common/lib/xmlenc-0.52.jar:/usr/local/hadoop/share/hadoop/common/lib/httpcore-4.2.5.jar:/usr/local/hadoop/share/hadoop/common/lib/commons-configuration-1.6.jar:/usr/local/hadoop/share/hadoop/common/lib/jackson-core-asl-1.8.8.jar:/usr/local/hadoop/share/hadoop/common/lib/commons-io-2.4.jar:/usr/local/hadoop/share/hadoop/common/lib/guava-11.0.2.jar:/usr/local/hadoop/share/hadoop/common/lib/jasper-compiler-5.5.23.jar:/usr/local/hadoop/share/hadoop/common/lib/activation-1.1.jar:/usr/local/hadoop/share/hadoop/common/lib/commons-lang-2.6.jar:/usr/local/hadoop/share/hadoop/common/lib/jersey-json-1.9.jar:/usr/local/hadoop/share/hadoop/common/lib/jets3t-0.9.0.jar:/usr/local/hadoop/share/hadoop/common/lib/commons-beanutils-core-1.8.0.jar:/usr/local/hadoop/share/hadoop/common/lib/commons-collections-3.2.1.jar:/usr/local/hadoop/share/hadoop/common/lib/commons-math3-3.1.1.jar:/usr/local/hadoop/share/hadoop/common/lib/commons-el-1.0.jar:/usr/local/hadoop/share/hadoop/common/lib/asm-3.2.jar:/usr/local/hadoop/share/hadoop/common/lib/jersey-core-1.9.jar:/usr/local/hadoop/share/hadoop/common/lib/netty-3.6.2.Final.jar:/usr/local/hadoop/share/hadoop/common/lib/commons-digester-1.8.jar:/usr/local/hadoop/share/hadoop/common/lib/jersey-server-1.9.jar:/usr/local/hadoop/share/hadoop/common/lib/snappy-java-*.jar
STARTUP_MSG: build = http://svn.apache.org/repos/asf/hadoop/common -r 1583262; compiled by 'jenkins' on 2014-03-31T08:29Z
STARTUP_MSG: java = 1.7.0_55
14/05/21 12:33:50 INFO namenode.NameNode: registered UNIX signal handlers for [TERM, HUP, INT]
14/05/21 12:33:50 INFO namenode.NameNode: createNameNode [-format]
14/05/21 12:33:51 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
Formatting using clusterid: CID-fcb97223-8452-4534-bf0d-23a9c0ce42df
14/05/21 12:33:51 INFO namenode.FSNamesystem: fsLock is fair:true
14/05/21 12:33:51 INFO namenode.HostFileManager: read includes:
14/05/21 12:33:51 INFO namenode.HostFileManager: read excludes:
14/05/21 12:33:51 INFO blockmanagement.DatanodeManager: dfs.block.invalidate.limit=1000
14/05/21 12:33:51 INFO blockmanagement.DatanodeManager: dfs.namenode.datanode.registration.ip-hostname-check=true
14/05/21 12:33:51 INFO util.GSet: Computing capacity for map BlocksMap
14/05/21 12:33:51 INFO util.GSet: VM type = 64-bit
14/05/21 12:33:51 INFO util.GSet: 2.0% max memory 966.7 MB = 19.3 MB
14/05/21 12:33:51 INFO util.GSet: capacity = 2^21 = 2097152 entries
14/05/21 12:33:51 INFO blockmanagement.BlockManager: dfs.block.access.token.enable=false
14/05/21 12:33:51 INFO blockmanagement.BlockManager: defaultReplication = 1
14/05/21 12:33:51 INFO blockmanagement.BlockManager: maxReplication = 512
14/05/21 12:33:51 INFO blockmanagement.BlockManager: minReplication = 1
14/05/21 12:33:51 INFO blockmanagement.BlockManager: maxReplicationStreams = 2
14/05/21 12:33:51 INFO blockmanagement.BlockManager: shouldCheckForEnoughRacks = false
14/05/21 12:33:51 INFO blockmanagement.BlockManager: replicationRecheckInterval = 3000
14/05/21 12:33:51 INFO blockmanagement.BlockManager: encryptDataTransfer = false
14/05/21 12:33:51 INFO blockmanagement.BlockManager: maxNumBlocksToLog = 1000
14/05/21 12:33:51 INFO namenode.FSNamesystem: fsOwner = hadoop (auth:SIMPLE)
14/05/21 12:33:51 INFO namenode.FSNamesystem: supergroup = supergroup
14/05/21 12:33:51 INFO namenode.FSNamesystem: isPermissionEnabled = true
14/05/21 12:33:51 INFO namenode.FSNamesystem: HA Enabled: false
14/05/21 12:33:51 INFO namenode.FSNamesystem: Append Enabled: true
14/05/21 12:33:51 INFO util.GSet: Computing capacity for map INodeMap
14/05/21 12:33:51 INFO util.GSet: VM type = 64-bit
14/05/21 12:33:51 INFO util.GSet: 1.0% max memory 966.7 MB = 9.7 MB
14/05/21 12:33:51 INFO util.GSet: capacity = 2^20 = 1048576 entries
14/05/21 12:33:51 INFO namenode.NameNode: Caching file names occuring more than 10 times
14/05/21 12:33:51 INFO util.GSet: Computing capacity for map cachedBlocks
14/05/21 12:33:51 INFO util.GSet: VM type = 64-bit
14/05/21 12:33:51 INFO util.GSet: 0.25% max memory 966.7 MB = 2.4 MB
14/05/21 12:33:51 INFO util.GSet: capacity = 2^18 = 262144 entries
14/05/21 12:33:51 INFO namenode.FSNamesystem: dfs.namenode.safemode.threshold-pct = 0.9990000128746033
14/05/21 12:33:51 INFO namenode.FSNamesystem: dfs.namenode.safemode.min.datanodes = 0
14/05/21 12:33:51 INFO namenode.FSNamesystem: dfs.namenode.safemode.extension = 30000
14/05/21 12:33:51 INFO namenode.FSNamesystem: Retry cache on namenode is enabled
14/05/21 12:33:51 INFO namenode.FSNamesystem: Retry cache will use 0.03 of total heap and retry cache entry expiry time is 600000 millis
14/05/21 12:33:51 INFO util.GSet: Computing capacity for map NameNodeRetryCache
14/05/21 12:33:51 INFO util.GSet: VM type = 64-bit
14/05/21 12:33:51 INFO util.GSet: 0.029999999329447746% max memory 966.7 MB = 297.0 KB
14/05/21 12:33:51 INFO util.GSet: capacity = 2^15 = 32768 entries
14/05/21 12:33:51 INFO namenode.AclConfigFlag: ACLs enabled? false
Re-format filesystem in Storage Directory /home/hadoop/hadoopspace/hdfs/namenode ? (Y or N) Y
14/05/21 12:34:10 INFO namenode.FSImage: Allocated new BlockPoolId: BP-614723417-
14/05/21 12:34:10 INFO common.Storage: Storage directory /home/hadoop/hadoopspace/hdfs/namenode has been successfully formatted.
14/05/21 12:34:10 INFO namenode.NNStorageRetentionManager: Going to retain 1 images with txid >= 0
14/05/21 12:34:10 INFO util.ExitUtil: Exiting with status 0
14/05/21 12:34:10 INFO namenode.NameNode: SHUTDOWN_MSG:
SHUTDOWN_MSG: Shutting down NameNode at hadoop-spark-vm/
[hadoop@hadoop-spark-vm hadoop]$ start-dfs.sh
14/05/21 12:35:04 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
Starting namenodes on [localhost]
localhost: starting namenode, logging to /usr/local/hadoop/logs/hadoop-hadoop-namenode-hadoop-spark-vm.out
localhost: starting datanode, logging to /usr/local/hadoop/logs/hadoop-hadoop-datanode-hadoop-spark-vm.out
Starting secondary namenodes []
The authenticity of host ' (' can't be established.
RSA key fingerprint is 6b:bc:6d:99:e5:88:52:29:07:cc:e3:bb:b9:dd:af:0b.
Are you sure you want to continue connecting (yes/no)? yes Warning: Permanently added '' (RSA) to the list of known hosts. starting secondarynamenode, logging to /usr/local/hadoop/logs/hadoop-hadoop-secondarynamenode-hadoop-spark-vm.out
14/05/21 12:35:27 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
[hadoop@hadoop-spark-vm hadoop]$ start-yarn.sh
starting yarn daemons
starting resourcemanager, logging to /usr/local/hadoop/logs/yarn-hadoop-resourcemanager-hadoop-spark-vm.out
localhost: starting nodemanager, logging to /usr/local/hadoop/logs/yarn-hadoop-nodemanager-hadoop-spark-vm.out

Issue the jps command and verify that the following jobs are running:

[hadoop@hadoop-spark-vm hadoop]$ jps
2795 NodeManager
2326 NameNode
2576 SecondaryNameNode
2434 DataNode
2710 ResourceManager
3091 Jps

Now you can try to create some hadoop directories by running

[hadoop@hadoop-spark-vm hadoop]$ hadoop fs -mkdir /test

And verify it is created by running:

[hadoop@hadoop-spark-vm hadoop]$ hadoop fs -ls /
drwxr-xr-x - hadoop supergroup 0 2014-05-21 14:21 /test

This tutorial was followed on AJ’S DATA STORAGE TUTORIALS, and I modified it to suit my own environment.