Linux Remote Desktop Display

One very annoying thing about Linux’s Remote Desktop (rdesktop) command is that you rarely can get a good screen size when remotely connecting to a Windows machine. It’s either too long and you have to always scroll, or worse yet, you are looking at an 800×600 view of your remote desktop.

Fortunately, the Linux crew has thought of a consistent way to get around this issue. You can tell rdesktop to run in full-screen mode initially. This is a terrific way to automatically get a desktop that fits your monitor’s screen size from the get go. To run in full-screen mode, run the following command –>

>rdesktop -f MyMachine

That’s it! You will have a screen that is fully sized to your monitor. One other thing – To break out of full screen mode, press Ctrl-Alt-Enter. Press Ctrl-Alt-Enter again to return to full-screen mode once again.

Using Verifone RiTA software with IBM WAS

If you are running the RiTA software by Verifone, you may encounter a number of issues configuring the software to work in an IBM WebSphere environment. There are two issues you want to avoid:

  • Not being able to find the tid.jcc file
  • Not having the .jar files in the correct location

First, the tid.jcc needs to be in the default server directory for IBM WAS. On Linux, this will most likely be the /opt/IBM/WebSphere/AppServer/profiles/AppSrv01 directory.

To add the tid.jcc reference, you will want to link it from your RiTA installation directory (the default directory being /opt/rita). Run these commands:

>cd /opt/IBM/WebSphere/AppServer/profiles/AppSrv01
>ln -s /opt/rita/tid.jcc

Next, you will need to link all of the RiTA .jar files to your extensions directory in the Java Runtime Engine. Run these commands:

>cd /opt/IBM/WebSphere/AppServer/java/jre/lib/ext
>find /opt/rita/lib/rita -name ‘*.jar’ -exec ln -s {} \;

You will now have symbolic links to all of the RiTA .jar files and it will be accessible to WebSphere and all other Java applications.

Jasper Server could not insert error

In Jasper Server, you may encounter the following error:

org.hibernate.exception.GenericJDBCException: could not insert: [com.jaspersoft lipitor 10mg.jasperserver.api.metadata.common.service.impl.hibernate.persistent.ContentRepoFileResource]

This can be caused by having too many automated reports stored in your Content Files directory. Especially if there are number of large .xls (or any type of file).

Just be sure to keep this directory to less than 50 files, and you should be good!

Setting up a classless DNS with Bind9 on Ubuntu and Red Hat Linux flavors

Setting up a classless DNS is critical if you are setting up a mail server on your classless set of IPs. For instance, when my mail users send e-mails to Comcast, Cox, or Time-Warner, my mail is rejected with the following message between the stars:

********************

Subject: Undelivered Mail Returned to Sender

This is the mail system at host melon.skky.net.

I’m sorry to have to inform you that your message could not be delivered to one or more recipients. It’s attached below.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can delete your own text from the attached returned message.

                   The mail system

<mailto:ddietrich@@socal.rr.com>: host hrndva-smtpin02.mail.rr.com[71.74.56.244] refused to talk to me: 421 4.7.1 – Connection refused.  Cannot resolve PTR record for 216.23.169.107

********************

In order to resolve this issue, you must ask your hosting provider to forward reverse DNS queries to your DNS server. Then, you can set up the reverse DNS for your classless range of IPs. Start by editing your named.conf file (/etc/bind/named.conf on Ubuntu, /var/named/chroot/etc/named.conf on Red Hat flavors). Add the following lines–>

zone “96/28.169.23.216.in-addr.arpa” {
 type master;
 file “/etc/bind/96-28.169.23.216.rev”;
};

In my case, my provider assigned me the range of 216.23.169.23.96-216.23.169.110. This is a /28 set of addresses. Notice how we reverse the zone entry. The Class D first, followed by a /, followed by the .Class C.Class B.Class A.in-addr.arpa. The filename roughly matches this as well. I called the file 96-28.169.23.216.rev. Just put this file in your /etc/bind directory on Ubuntu, or /var/named/chroot/var/named on Red Hat Linux flavors (RH5, CentOS, Fedora Core, etc.)

Now for the actual file 96-28.169.23.216.rev contents between the stars –>

****************************

$ttl 38400
$ORIGIN 96/28.169.23.216.in-addr.arpa.
@       1D      IN      SOA     ns1.wiretoss.com. ddietrich.localhost. (
                        1172404866
                        10800
                        3600
                        604800
                        38400 )
        NS      ns1.wiretoss.com.
        NS      ns2.wiretoss.com.
100     PTR     ns1.vitaven.com.
101     PTR     101.wiretoss.com.
102     PTR     102.wiretoss.com.
103     PTR     103.wiretoss.com.
104     PTR     104.wiretoss.com.
105     PTR     105.wiretoss.com.
106     PTR     106.wiretoss.com.
107     PTR     ns1.wiretoss.com.
108     PTR     108.wiretoss.com.
109     PTR     109.wiretoss.com.
110     PTR     110.wiretoss.com.
****************************

Restart bind9 and you should now have a happy reverse DNS to the rest of the world, and especially those pesky mail servers that check for everything.

Samba – Stop homes from showing in shares

When using Samba on Linux, there are times that you want to allow user to have a private user directory, but do not want the “homes” directory share to show up. This is relatively simple.

Edit your /etc/samba/smb.conf file with your favorite Linux editor.
Look for the section [homes] and find the line
browseable =

set this line to browseable = no

Restart Samba (>service smb restart) and your users should now see their personal directory without seeing the homes share.

If you do not have a [homes] section, here is an example on for you –>

[homes]
        hide dot files = no
        comment = Home Directories
        writeable = yes
        delete readonly = yes
        valid users = %S
        browseable = no

Initializing a new instance of Linux

After a fresh install of Linux, there are a number of tasks I like to do. I like having commands and aliases that I am used to installed.

Copy /opt/scripts

Create /opt/sw

/opt/scripts/stopUnusedServices.sh

set up MySQL

Install WebMin and VirtualMin for managing your domain names and their.

Connecting Red Hat 5.3 to a Dell MD3000i

Connecting to a DELL MD3000i is no trivial matter with Linux. First, you need to ensure that you have the DKMS package installed.

>yum -y install dkms
>yum -y install iscsi-initiator-utils
>yum -y install gcc
>yum -y install kernel-devel
>yum -y install sgpio
>yum -y install sg3_utils

Now you can install the Dell Tools and finish configuring your SAN.

Jasper Server Permission Denied error

Occasionally, Jasper Server has an error relating to being unable to write files. The errors show up in the Apache web server log, catalina.out.

You have probably started the service as the user root on accident. This will cause ownership to change to root on some log files. Then when you log back on as user jasper and restart your server, the Apache logs are filling with messages about not being able to write files. Jasper is just not working properly. Run the following command to restore the proper ownership to all files in the Jasper directory. You must run the following command as root:

>find /home/jasper/jasper-server-3.7 -user root -exec chown jasper.jasper {} \;

This will find all the files that root changed ownership and change the ownership back to the proper jasper user.

Linux overwrites DNS resolver /etc/resolv.conf

Linux will overwrite your /etc/resolv.conf in 3 cases. If you have:

  1. Network Manager enabled.
    Disable the Network Manager by turning it off with the following commands:
    >service NetworkManager stop
    >chkconfig NetworkManager off        

  2. DHCP enabled.
    dhcpd will overwrite your /etc/resolv.conf when it acquires an IP address. Convert to a static IP if you are in control of the network.
  3. DNS1, DNS2 or any other DNS# entries in any of your network interface configurations.
    If you are the administrator of this machine, check every file matching the following pattern:
    >find /etc/sysconfig/network-scripts/ifcfg-*
    and look for any DNS# entries in every matching file. If you find any DNS# lines, and if you are root, remark the lines by inserting a # sign at the beginning of the DNS# line.
    Save the file(s) lipitor cost.
    Then run –>
    >service network restart

Once you’ve gone through these 3 items, you should be able to now edit and save your /etc/resolv.conf file. Verify that the file no longer is being overwritten. Just execute >cat /etc/resolv.conf a few times for a few minutes and verify the file is no longer changing. Also >reboot the machine to be extra sure nothing changes in the /etc/resolv.conf file.