Tuesday, March 11, 2014

Time not showing in Roundcube. ( Date column is blank)

When you installed Roundcube Mails are showing properly but the time of emails do not show.
This issue occurred due to php.ini file configuration.

You need to set correct time zone in the php.ini file.
vi /etc/php.ini
date.timezone = "UTC"

 then restart the apache service. That's all. Enjoy it.  

Monday, November 11, 2013

Wired Network Unstable with Ubuntu 13.04

I have installed 13.04 64bit OS in Toshibha laptop. I have connected the Wired network but the issue is that connection is getting drop time to time even Network stayed connected.
I could not ping to the gateway. Then I have restart the network but the problem remain same. After physically unplugged & plugged the cable,the network is back to normal. But the issue is that this can not be done frequently.
So to overcome this issue I have followed the below step.
  1. Found out that this issue is due to kernel bug in 3.8 version.
  2. Then I have gone for a kernel upgrade to version 3.10, to do that use the below commands.
wget http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.10.12-saucy/linux-headers-3.10.12-031012-generic_3.10.12-031012.201309141044_amd64.deb
wget http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.10.12-saucy/linux-headers-3.10.12-031012_3.10.12-031012.201309141044_all.deb

wget http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.10.12-saucy/linux-image-3.10.12-031012-generic_3.10.12-031012.201309141044_amd64.deb
sudo dpkg -i linux-headers-3.10.12-*.deb linux-image-3.10.12*.deb
Then Restart the computer.

After the reboot I have make ping to gateway and worked as usual. Continuously for 2 hours able to ping to gateway. So this is the way to solve the instability of network connection issue in Ubuntu 13.04 OS.

Tuesday, August 6, 2013

Peer to Peer communication in FreePBX

This document pointing out the Direct RTP media or peer to peer communication of RTP.

I have managed to get Asterisk not to proxy media. I am running Freepbx 2.10.1.9 and Asterisk 1.8.12.0 on CentOS Linux 5.7 (Linux 2.6.18-274.3.1.el15.i686 - 32-bit) in Virtual machine. Directly connected to static IP.

It can be done under below conditions.
    --> NAT should be disabled in the FreePBX ( sip.conf, Extension)
    --> Network Devices and Phones should support for peer to peer communication (NO NAT)
    --> In the extensions recording features should be turned off.
    --> Should havedirect internet connection with static IP address

Setting changes in the SIP server, this is should be done via freepbx GUI
    1) Application -> Extensions -> 'canreinvite=yes' and 'nat=no'
    2) Settings -> Asterix SIP settings -> 'NAT=no' and 'IPconfiguratoin=static IP' and 'Reinvite Behavior=yes'
    3) Add below entries to Other SIP Settings
        --> 'directrtpsetup=yes' and
        --> 'keepalive=yes'
    4) Settings -> Advanced Settings -> "SIP canrenivite (directmedia)=yes" and "SIP nat=no"
    5) Settings -> General Settings -> "Asterisk Dial command options:" should be empty


I have used tcpdump tool to monitor the communicatoin between server and SIP phones. Then I were albe to recognized the peer to peer communication.




Reference : http://www.dslreports.com/forum/r27852319-Can-I-get-Asterisk-to-not-proxy-media-

Friday, June 7, 2013

check_mailq not correctly detecting the mail queue -NRPE plugins


I have added nagios NRPE client to check mail queue in CentOS 6 server and running postfix as mail deamon.

Issue : Eventhough there is mailq in the server nagios showed as Empty mailq.


First I checked the below configuration files in the Mail server
--> /usr/local/nagios/libexec/check_mailq : There you can find a variable called
"$mailq = 'sendmail'; # default". I have changed it to postfix. But it didnt resolve the issue.
--> /usr/local/nagios/libexec/utils.pm : There you can find a varialbe called $PATH_TO_MAILQ   = "/usr/bin/mailq";
This is also correct. That can checked by issue /usr/bin/mailq and it will show the actual mailq
--> /usr/local/nagios/etc/nrpe.cfg : There you set check_mailq parameteres
/usr/local/nagios/libexec/check_mailq -w 100 -c 200

Run the below command independantly in the mail server
--> /usr/local/nagios/libexec/check_mailq -w 100 -c 200
But it issues the Mail queue empty though there are several mails in the queue.

Then I issued the above command with the mail deamon option as below
--> /usr/local/nagios/libexec/check_mailq -w 100 -c 200 -M postfix
This will show you the correct mail queue and then I chaged the /usr/local/nagios/etc/nrpe.cfg check_mailq parameter with the -M postfix option.
Issue was sorted.

Note : AS far as I found the postfix does not create mailqueue directory under /var/spool/. It has seperate direcotry in /var/spool/postfix/ which maintain mails in seperate directories such as  deferred , bounce , active  etc. So this might be the reason the nagion NRPE plugin could not check the mail queue correctly.

Some of the packages cannot updated. Need to take from old packages.


Ubuntu apt-get install propagate error message “ Some of the packages cannot updated. Need to take from old packages. - Ubuntu OS version is old.”


When you get this kind of error message first you need to backup /etc/apt/souces.list and then follow the below mention steps.

  1. vi /etc/apt/sources.list
  2. Then find the below lines and replace as mention
  • deb <siteurl> karmic main restricted
  • replace the <siteurl> with http://old-releases.ubuntu.com/ubuntu
3. Once again find http://security.ubuntu.com/ubuntu and replace with http://old-releases.ubuntu.com/ubuntu

4. Save the changes and issue the below command.
5. apt-get update

Then install the packages as you wish.

Friday, May 17, 2013

SELinux is preventing /sbin/iptables-multi-1.4.7 from read access on the file

Error message :
Check the /var/log/messages to get idea of error
=========================================================================
May 12 04:05:40 mail setroubleshoot: SELinux is preventing /sbin/iptables-multi-1.4.7 from read access on the file . For complete SELinux messages. run
sealert -l 1a33e373-0b4e-4e1c-8cf7-38636b5acbde
May 12 04:05:40 mail setroubleshoot: SELinux is preventing /sbin/iptables-multi-1.4.7 from create access on the rawip_socket . For complete SELinux mes
sages. run sealert -l c2931169-d03b-4758-92d4-f22275f7f391
May 12 04:05:40 mail setroubleshoot: SELinux is preventing /sbin/iptables-multi-1.4.7 from create access on the rawip_socket . For complete SELinux mes
sages. run sealert -l c2931169-d03b-4758-92d4-f22275f7f391
May 12 04:05:40 mail setroubleshoot: SELinux is preventing /sbin/iptables-multi-1.4.7 from read access on the file . For complete SELinux messages. run
sealert -l 1a33e373-0b4e-4e1c-8cf7-38636b5acbde
May 12 04:05:37 mail fail2ban.actions: WARNING [dovecot-pop3imap] Unban 125.19.48.106
May 12 04:05:37 mail fail2ban.actions.action: ERROR iptables -n -L INPUT | grep -q 'fail2ban-dovecot-pop3imap[ \t]' returned 100
May 12 04:05:37 mail fail2ban.actions.action: ERROR Invariant check failed. Trying to restore a sane environment
May 12 04:05:37 mail fail2ban.actions.action: ERROR iptables -D INPUT -p tcp -m multiport --dports pop3,pop3s,imap,imaps -j fail2ban-dovecot-pop3imap#
012iptables -F fail2ban-dovecot-pop3imap#012iptables -X fail2ban-dovecot-pop3imap returned 300
May 12 04:05:37 mail fail2ban.actions.action: ERROR iptables -N fail2ban-dovecot-pop3imap#012iptables -A fail2ban-dovecot-pop3imap -j RETURN#012iptabl
es -I INPUT -p tcp -m multiport --dports pop3,pop3s,imap,imaps -j fail2ban-dovecot-pop3imap returned 100
May 12 04:05:37 mail fail2ban.actions.action: ERROR iptables -n -L INPUT | grep -q 'fail2ban-dovecot-pop3imap[ \t]' returned 100
May 12 04:05:37 mail fail2ban.actions.action: CRITICAL Unable to restore environment
================================================================================

This error propagate with the Selinux, you can run the below command to get fully idea about selinux error.
sealert -l 1a33e373-0b4e-4e1c-8cf7-38636b5acbde

Check the audit.log file and find below deined messages.
type=AVC msg=audit(1368773459.619:3055): avc: denied { read } for pid=6627 comm="iptables" scontext=unconfined_u:system_r:fail2ban_t:s0 tcontext=system_u:object_r:sysctl_modprobe_t:s0 tclass=file
type=AVC msg=audit(1368773459.620:3056): avc: denied { create } for pid=6625 comm="iptables" scontext=unconfined_u:system_r:fail2ban_t:s0 tcontext=unconfined_u:system_r:fail2ban_t:s0 tclass=rawip_socket
type=AVC msg=audit(1368773459.620:3057): avc: denied { read } for pid=6625 comm="iptables" scontext=unconfined_u:system_r:fail2ban_t:s0 tcontext=system_u:object_r:sysctl_modprobe_t:s0 tclass=file
type=AVC msg=audit(1368773459.622:3058): avc: denied { create } for pid=6629 comm="iptables" scontext=unconfined_u:system_r:fail2ban_t:s0 tcontext=unconfined_u:system_r:fail2ban_t:s0


Resolution :


Once I check the context of /sbin/iptables-multi-1.4.7 it will show the incorrect context as below

  • ls -lZ /sbin/iptables-multi-1.4.7
output
  • -rwxr-xr-x. root root system_u:object_r:bin_t:s0       /sbin/iptables-multi-1.4.7
Run the below command to correct the Selinux context

  • restorecon -R -v /sbin/

then run the ls -lZ command which show the correct context

  • -rwxr-xr-x. root root system_u:object_r:iptables_exec_t:s0 /sbin/iptables-multi-1.4.7

Then restart the fail2ban service.


Tuesday, May 14, 2013

Samba Server configuration -CentOS 6.3 with SeLinux

You must installs below packages in order to configure as samba server
yum install cups-libs samba samba-common

Initially you must allow firewall to access to samba server. Below ports should be allowed. In my server I have used iptables as firewall so below rules will allow the samba from firewall

-A INPUT -m state --state NEW -m tcp -p tcp -s 192.168.1.0/24 --dport 137 -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp -s 192.168.1.0/24 --dport 138 -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp -s 192.168.1.0/24 --dport 139 -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp -s 192.168.1.0/24 --dport 445 -j ACCEPT
you can restrict by source IP from better security.

Then you need to concern about SeLinux values. Since if you not enable boolean value then even home directory not be able to share.

If you want to share the default home directory, type this command:
setsebool -P samba_enable_home_dirs on
If you want samba to be a domain controller:
setsebool -P samba_domain_controller on
If you want to share files/directories other than home directories or standard directory. You should label these files/directories as samba_share_t. For example if you created the directory /home/fileserver, you can label the directory and its contents with the chcon tool.

# chcon -R -t samba_share_t /home/fileserver
To make this label permanent issue the below commands.
# semanage fcontext -a -t samba_share_t ’/home/fileserver(/.*)?’
# restorecon -R -v /home/fileserver

There are two booleans that you can set to allow the sharing of standard directories. If you want to share any standard directory read/only you can set the boolean samba_export_all_ro.
# setsebool -P samba_export_all_ro 1
This boolean will allow Samba to read every file on the system.Similarly if you want to share all files and directories via Samba, you set the samba_export_all_rw
# setsebool -P samba_export_all_rw 1
This boolean would allow Samba to read and write every file on your system.  So a compromised Samba server would be very dangerous.

for more details please refer below link :

Then you need to configure the smb.conf file as you want.

I have configured home and other shared directories and my configuration file should be as below.

[Common]
comment = All Users
path = /home/common
valid users =@users
force group = users
create mask = 0765
directory mask = 0775
writable = yes

If you need to enable home directories that users can read and write to it below entry should be included.

[homes]
   comment = Home Directories
   browseable = no
   valid users = %S
   writable = yes
   create mask = 0700
   directory mask = 0700
Now add the user to the Samba user database:
smbpasswd -a tom