Jontas

WordPress 3: Super Admin pulled a disappearing act

jontas — Wed, 08 Sep 2010 08:54:59 +0000

Had a slight problem after the database server had to make a unplanned reboot.
I have a Network running on the WordPress installation; the sites were working, the dashboard was working however I did not have the insert image icon in the posts and the Super Admin was not visible.

For me this turned out to be a simple. The database table “wp_sitemeta” was marked as crashed and could not be read by WordPress.

This is likely to be the problem if the Super Admin disappeared after a hard shutdown of the database server. (By hard I mean that the database didn’t have time to close tables, finish writing to tables etc)

OpenVPN giving a client a static IP

jontas — Tue, 31 Aug 2010 08:46:16 +0000

To set up static IP for a client first set up client-config’s in server.conf

# EXAMPLE: Suppose the client
# having the certificate common name "Thelonious"
# also has a small subnet behind his connecting
# machine, such as 192.168.40.128/255.255.255.248.
# First, uncomment out these lines:
client-config-dir client-configs

Then create the directory “/etc/openvpn/client-configs
Then create a file with the name of the client that is connecting in this folder
(for instance “/etc/openvpn/client-configs/backup”)

#Give this machine 10.8.0.3 a a static ip
ifconfig-push 10.8.0.3 10.8.0.0

(Remember to replace with values that makes sense to you)

OpenVPN: TLS Error: reading acknowledgement record from packet

jontas — Mon, 30 Aug 2010 15:00:59 +0000

This error message (in my experince) most often means that one side (either the client or the server) is set up for TLS auth, but the other side is not.

Check both configs and fix this problem.

To add it to a client
Copy the file /etc/openvpn/ta.key from the server to the client
and then edit /etc/openvpn/myVpn.conf

# If a tls-auth key is used on the server
# then every client must also have the key.
tls-auth ta.key 1

Adding a OpenVPN client on ubuntu 10.04

jontas — Mon, 30 Aug 2010 13:20:37 +0000

First the certificate (key) should be created on the server.

cd /etc/openvpn/easy-rsa/
source vars
./pkitool hostname

Copy the certificate files to the client
* /etc/openvpn/ca.crt
* /etc/openvpn/easy-rsa/keys/hostname.crt
* /etc/openvpn/easy-rsa/keys/hostname.key

Then the client should be setup

apt-get install openvpn
cd /etc/openvpn
cp /usr/share/doc/openvpn/examples/sample-config/client.conf client.conf

Edit the client.conf file (edit all that you need to fit your config, the following are those I recommend):
The fix for Vista I add (commented out) since I am lazy and usually just copy a old config file to the next client

remote my.domain.com 1194
 
# a separate .crt/.key file pair
# for each client.  A single ca
# file can be used for all clients.
ca ca.crt
cert clientName.crt
key clientName.key
 
#fix for vista being stuid...
;route-method exe
;route-delay 2

Restart OpenVPN on the client:

 /etc/init.d/openvpn restart
 * Stopping virtual private network daemon(s)...                                
 *   No VPN is running.
 * Starting virtual private network daemon(s)...                                
 *   Autostarting VPN 'medihand'                                         [ OK ]

Same as with the server, the above means that is went well, a [fail] means that the logs should be read for details.

A word of caution: [ OK ] only means that the OpenVPN was started ok – no errors in config etc.
There might still be issues with firewalls, wrong hostname (to the server) etc.
Check ifconfig and ping the server to make sure it is working.

Installing OpenVPN (server) on ubuntu 10.04

jontas — Mon, 30 Aug 2010 12:39:44 +0000

This is a quick note on how to install OpenVPN as a Ethernet tunnel (not a bridge) on ubuntu 10.04

install

sudo apt-get install openvpn

Server Certificates

First, copy the easy-rsa directory to /etc/openvpn.

sudo mkdir /etc/openvpn/easy-rsa/
sudo cp -r /usr/share/doc/openvpn/examples/easy-rsa/2.0/* /etc/openvpn/easy-rsa/

You may also wish to adjust permissions in the easy-rsa directory to allow the current user permission to create files.

sudo chown -R $USER /etc/openvpn/easy-rsa/

Next, edit /etc/openvpn/easy-rsa/vars but make sure you adjust at least the following values to values make sense to you:

export KEY_COUNTRY="SE"
export KEY_PROVINCE="Blekinge"
export KEY_CITY="Karlskrona"
export KEY_ORG="My organization"
export KEY_EMAIL="vpnhelp@example.com"

Enter the following to create the server certificates:

cd /etc/openvpn/easy-rsa/
source vars
./clean-all
./build-dh
./pkitool --initca
./pkitool --server server
cd keys
openvpn --genkey --secret ta.key
sudo cp server.crt server.key ca.crt dh1024.pem ta.key /etc/openvpn/

Server Configuration
Lets start by copying the example config.

sudo cp /usr/share/doc/openvpn/examples/sample-config-files/server.conf.gz /etc/openvpn/
sudo gunzip /etc/openvpn/server.conf.gz

Edit /etc/openvpn/server.conf changing (at least) the following options (change to values that make sense to you):

#Change the VPN subnet address to one that makes sense to you (and don't collide with any other net)
server 10.9.0.0 255.255.255.0
#If you wish the computers on the VPN to be able to connect to each other then uncomment
client-to-client
# You can uncomment this out on
# non-Windows systems.
user nobody
group nogroup
#If this is uncommented then a separate log will be written for OpenVPN (If both log lines are uncommented, then syslog is used)
log-append  openvpn.log
#To enable per client configurations uncomment:
client-config-dir client-configs

Restart the VPN:

/etc/init.d/openvpn restart

If the server failed to start:

/etc/init.d/openvpn restart
 * Stopping virtual private network daemon(s)...                                                                                                 
 *   No VPN is running.
 * Starting virtual private network daemon(s)...                                                                                                 
 *   Autostarting VPN 'server'                                                     [fail]

Then you should check out the log (either syslog or the log you set in the config file) and solve the issues.
It should look like this:

/etc/init.d/openvpn restart
 * Stopping virtual private network daemon(s)...                                                                                                 
 *   No VPN is running.
 * Starting virtual private network daemon(s)...                                                                                                 
 *   Autostarting VPN 'server'                                                     [ OK ]

Linux send a log as a mail from the linux console

jontas — Wed, 18 Aug 2010 11:00:22 +0000

Sometimes it is nice to send a log or some other file as a email to someone (or a part of a file)

cat myfile.txt | mail -s 'SUBJECT' example@mail.com;

Change myfile.txt, SUBJECT and example@mail.com to something useful.

MySQL execute statements directly from the (linux) console

jontas — Wed, 18 Aug 2010 09:16:06 +0000

Executing a query quickly from the console is nice to be able to do (without having to enter the MySQL console).

This will simply output the result to the console where you are.
```
 user@server:~$ mysql -uUSERNAME -p TABLENAME --execute "REPAIR TABLE position";
```
Replace USERNAME and TABLENAME with your vars
If you would like the output to a file
```
 mysql -uUSERNAME -p TABLENAME --execute "SELECT * FROM test" > test.sql;
```
Replace USERNAME and TABLENAME with your vars
If you would like the output to be sent as a email
```
 mysql -uUSERNAME -p TABLENAME --execute "SELECT * FROM test" | mail -s 'SUBJECT' example@mail.com
```
Replace USERNAME, TABLENAME, SUBJECT and example@mail.com with your vars

Windows XP: Keep ie6 installed (don’t update ie)

jontas — Wed, 11 Aug 2010 08:46:33 +0000

Keeping Internet Explorer 6 installed and don’t update to a safe (and nice) version.
I only recommend doing this on a machine that should keep Internet Explorer 6 in order to do development testing.

Disable Internet Explorer 7 Open up a registry editor and check if the key “HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Setup\7.0″ exists, otherwise create it (the key is the tree structure in regedit).
Now enter a Key name “DoNotAllowIE70″ as a DWORD and give it the value “1″.
This will keep Internet Explorer 8 from installing on this computer.
Disable Internet Explorer 8 Open up a registry editor and check if the key “HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Setup\8.0″ exists, otherwise create it (the key is the tree structure in regedit).
Now enter a Key name “DoNotAllowIE80″ as a DWORD and give it the value “1″.
This will keep Internet Explorer 8 from installing on this computer.

The values mean the following:

When the key value name is not defined, distribution is not blocked.
When the key value name is set to 0, distribution is not blocked.
When the key value name is set to 1, distribution is blocked.

If you need to do this on several computers then you can download Toolkits to do this from Microsoft (warning: read the instructions and verify that you ran it correctly on the first computer you run it on):

Apache2 unseting AddDefaultCharset (via .htaccess)

jontas — Tue, 27 Jul 2010 11:19:35 +0000

Setting a default charset using .htaccess is a simple thing to do

However sometimes there is a need to unset default charset as well (for instance if the AddDefaultCharset is set in the apache config and this is causing problems).

This is very easy to do just edit the .htaccess file and add a line that says

AddDefaultCharset OFF

Linux: Finding the serial number of a hard drive

jontas — Fri, 23 Jul 2010 20:33:22 +0000

Finding the serial number of a hard drive on a Linux console (as root) is simple with the right tool.
The right tool in this case is hdparm (using the -i option).
-i will query the device directly for the details.

Example:

themachine:/proc# hdparm -i /dev/sda
 
/dev/sda:
 
 Model=ST31500341AS                            , FwRev=CC1H    , SerialNo=            9VS21ZXM
 Config={ HardSect NotMFM HdSw>15uSec Fixed DTR>10Mbs RotSpdTol>.5% }
 RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=4
 BuffType=unknown, BuffSize=0kB, MaxMultSect=16, MultSect=?16?
 CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=18446744072344861488
 IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120}
 PIO modes:  pio0 pio1 pio2 pio3 pio4 
 DMA modes:  mdma0 mdma1 mdma2 
 UDMA modes: udma0 udma1 udma2 udma3 udma4 udma5 *udma6 
 AdvancedPM=no WriteCache=enabled
 Drive conforms to: unknown:  ATA/ATAPI-4,5,6,7
 
 * signifies the current active mode

Using the option -I instead gives even more information:

themachine:/proc# hdparm -I /dev/sda
 
/dev/sda:
 
ATA device, with non-removable media
        Model Number:       ST31500341AS                            
        Serial Number:      9VS21ZXM
        Firmware Revision:  CC1H    
        Transport:          Serial
Standards:
        Used: unknown (minor revision code 0x0029) 
        Supported: 8 7 6 5 
        Likely used: 8
Configuration:
        Logical         max     current
        cylinders       16383   16383
        heads           16      16
        sectors/track   63      63
        --
        CHS current addressable sectors:   16514064
        LBA    user addressable sectors:  268435455
        LBA48  user addressable sectors: 2930277168
        device size with M = 1024*1024:     1430799 MBytes
        device size with M = 1000*1000:     1500301 MBytes (1500 GB)
Capabilities:
        LBA, IORDY(can be disabled)
        Queue depth: 32
        Standby timer values: spec'd by Standard, no device specific minimum
        R/W multiple sector transfer: Max = 16  Current = ?
        Recommended acoustic management value: 254, current value: 0
        DMA: mdma0 mdma1 mdma2 udma0 udma1 udma2 udma3 udma4 udma5 *udma6 
             Cycle time: min=120ns recommended=120ns
        PIO: pio0 pio1 pio2 pio3 pio4 
             Cycle time: no flow control=120ns  IORDY flow control=120ns
Commands/features:
        Enabled Supported:
           *    SMART feature set
                Security Mode feature set
           *    Power Management feature set
           *    Write cache
           *    Look-ahead
           *    Host Protected Area feature set
           *    WRITE_BUFFER command
           *    READ_BUFFER command
           *    DOWNLOAD_MICROCODE
                SET_MAX security extension
           *    Automatic Acoustic Management feature set
           *    48-bit Address feature set
           *    Device Configuration Overlay feature set
           *    Mandatory FLUSH_CACHE
           *    FLUSH_CACHE_EXT
           *    SMART error logging
           *    SMART self-test
           *    General Purpose Logging feature set
           *    WRITE_{DMA|MULTIPLE}_FUA_EXT
           *    64-bit World wide name
                Write-Read-Verify feature set
           *    WRITE_UNCORRECTABLE_EXT command
           *    {READ,WRITE}_DMA_EXT_GPL commands
           *    Segmented DOWNLOAD_MICROCODE
           *    SATA-I signaling speed (1.5Gb/s)
           *    SATA-II signaling speed (3.0Gb/s)
           *    Native Command Queueing (NCQ)
           *    Phy event counters
                Device-initiated interface power management
           *    Software settings preservation
           *    SMART Command Transport (SCT) feature set
           *    SCT Long Sector Access (AC1)
           *    SCT LBA Segment Access (AC2)
           *    SCT Error Recovery Control (AC3)
           *    SCT Features Control (AC4)
           *    SCT Data Tables (AC5)
                unknown 206[12] (vendor specific)
Security: 
        Master password revision code = 65534
                supported
        not     enabled
        not     locked
        not     frozen
        not     expired: security count
                supported: enhanced erase
        240min for SECURITY ERASE UNIT. 240min for ENHANCED SECURITY ERASE UNIT.
Logical Unit WWN Device Identifier: 5000c50014ec1f60
        NAA             : 5
        IEEE OUI        : c50
        Unique ID       : 014ec1f60
Checksum: correct