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showing posts tagged with 'computer'
 
iptables: block traffic from/to a specific IPv4 address
edited by on September 13th 2019, at 10:55
To quickly block traffic from/to a specific IPv4 address using iptables, you can use the commands below.

Warning!
Do not use these commands when you are already running an iptables-based firewall as this may result in unexpected results.

Block incoming traffic from a specific IP:

iptables -A INPUT -s 1.2.3.4 -j DROP

Block outgoing traffic (i.e. traffic initiated from the host itself) to a specific IP:

iptables -A OUTPUT -d 1.2.3.4 -j DROP

To block outgoing traffic to a specific port and protocol, you can also do something like this (the example below blocks DNS and HTTP):

/sbin/iptables -A OUTPUT -p tcp --dport 80 -d 1.2.3.4 -j DROP/sbin/iptables -A OUTPUT -p udp --dport 53 -d 1.2.3.4  ...
 
Revive your old Macbook with MacPostFactor
edited by on August 16th 2018, at 10:13
MacPostfactor is a tool to install Mac OSX 10.8+ on older Macbooks that normally only support up to OSX 10.7 (Lion). It works through a combination of a highly customized installer, a replaced set of drivers and various frameworks, and the original installation app from the App Store. The installation can be done directly on a Macbook already running OSX Lion (so no USB disk required), or on an USB media for installation on another system.

You need an Intel-based Macbook capable of running OSX Lion (10.7) (otherwise your Mac is too old), but one that does not support OSX Mountain Lion (10.8) or higher. PowerPC-based Macs are not supported (they do not run OSX Lion).

The installer app of th  ...
 
Set HTML auto-reply messages for shared/resource mailboxes in Office 365
edited by on December 19th 2017, at 09:11
Currently, it's not possible to set up HTML-based auto-reply messages on shared or resource mailboxes, as you cannot directly log on to OWA to set the message. Through Powershell, you can do this quite easily.

First, create two HTML-files containing your internal and external message. You do not have to specify the <html> and <body> tags. Save these to a convenient location. Be sure to save them as regular text files, with extension .txt.

Next, log on to Exchange Online management shell.

cd to the location of the two message files, and load them to variables:

$internalmessage = Get-Content -Path internalmessage.txt

$externalmessage = Get-Content -Path externalmessage.txt  ...
 
List of sysprep files for VMware Converter
edited by on July 24th 2017, at 17:19
In order to succesfully convert Windows systems to a VMware virtual machine, you need to install the sysprep files of the to be converted host. Below is a list of downloads to these sysprep files:

The base folder of where to put the files is always:

Quote
%ALLUSERSPROFILE%\Application Data\VMware\VMware vCenter Converter Standalone\sysprep

Extract contents to: base-folder\2k

Available in SP4 or the CD-ROM of Windows 2000 SP4 at Support\Tools\Deploy.cab

Extract contents to: base-folder\svr2003

Link: http://www.microsoft.com/en-us/download/details.aspx?id=14830.

Extract contents to: base-folder\svr2003-64

Link: http://www.microsoft.com/en-us/download/details.aspx?id=8287.

Extract cont  ...
 
List of VMware vSphere clients
edited by on June 26th 2017, at 09:53
A list with direct links to VMware vSphere clients. Saves you a lot of time when you need to (re)install many different versions.

Starting with 6.5, the vSphere client is no longer available.

VMware vSphere Client 6.0 Update 3: VMware-viclient-all-6.0.0-5112508.exe

VMware vSphere Client 6.0 Update 2a: VMware-viclient-all-6.0.0-4437566.exe

VMware vSphere Client 6.0 Update 2: VMware-viclient-all-6.0.0-3562874.exe

VMware vSphere Client 6.0 Update 1: VMware-viclient-all-6.0.0-3016447.exe

VMware vSphere Client 6.0: VMware-viclient-all-6.0.0-2502222.exe

VMware vSphere Client 5.5 Update 3d: VMware-viclient-all-5.5.0-3705931.exe

VMware vSphere Client 5.5 Update 3: VMware-viclient-all-5.5.0-3  ...
 
ESX host lost connection to vCenter? Check free ramdisk space!
edited by on January 10th 2017, at 14:42
If your ESX host has lost connection to the vCenter server, but you can still directly access the host's management, and can find nothing else wrong with the vCenter server or its network connection to the host, you may want to the free space on your ESX host.

Logs and other temporary files may have filled up one or more ramdisk partitions (e.g. when you don't have a persistent scratch partition, it gets mounted on /tmp). This can cause any of the following issues:

Connection loss between the ESX host and vCenter server;

Errors when attempting to reconnect or add an ESX host to a vCenter server;

Errors while attempting to activate or configure HA;

Other unexplainable errors...

You can   ...
 
Private MAC address ranges
edited by on August 16th 2016, at 14:30
Like private IP address ranges (defined in RFC 1918), there are also private MAC address ranges. These are called Locally Administered Address Ranges which are never used by devices or other vendors. MAC addresses in these ranges can be safely used, assuming they are unique within your network:

x2-xx-xx-xx-xx-xx

x6-xx-xx-xx-xx-xx

xA-xx-xx-xx-xx-xx

xE-xx-xx-xx-xx-xx

The ranges may seem odd but is explained best by this excerpt from Wikipedia:

Universally administered and locally administered addresses are distinguished by setting the second least significant bit of the most significant byte of the address. If the bit is 0, the address is universally administered. If it is 1, the address  ...
 
Safe CFLAGS
edited by on May 27th 2016, at 14:14

Found this page very useful when I had to compile some stuff for a Geode LX:

https://wiki.gentoo.org/wiki/Safe_CFLAGS

Note: this original post was from May 2007 but someone pointed out to me that the link no longer worked, in an attempt to sell me some web hosting... So... Thanks, but I'm sticking with my current hosting company.

 
Download links for Java SE 6, 7 and 8 (JRE and JDK)
edited by on September 11th 2015, at 11:31

Here are the download links for the old Java SE 6, 7 and 8 installers. You can download both the JRE and JDK from these pages.

(*) For Java SE 6 and 7, you'll need to create a free Oracle account to download.

 
Renew certificates on ADFS 3.0 (2012 R2)
edited by on August 24th 2015, at 16:20
Occasionally (usually once a year), you may have to renew your SSL certificate of your Active Directory Federation Services server, used for your Office 365 Single Sign-On setup. In past versions, this was done quite easily through IIS. However, since 2012 R2 (a.k.a. ADFS 3.0), ADFS no longer uses IIS and it gets a little bit more complicated.

Outlined in this short article are the steps you need to do in order to renew or replace your SSL certificate on a Windows 2012 R2 server, running ADFS 3.0.

First, renew or request a new SSL certificate through your Certificate Authority (such as GoDaddy, Enom, etc.). How to do this depends greatly on the CA. As ADFS on 2012 R2 no longer uses IIS, yo  ...
 
Configure DNS for Office 365 using DirectAdmin
edited by on August 17th 2015, at 13:25
EDIT: highlight required trailing dots + added CNAME for msoid.

If you're using a hosting provider which uses DirectAdmin for its DNS management, it may be a hassle to correctly configure DNS records for Office 365, mainly because of syntax issues. After some trial-and-error and googling, I finally managed to correctly devise the proper syntax to configure Exchange Online and Lync Online.

The set up of the entries below is a left and right field in the DNS management, safe for MX-records, which are set up elsewhere. For most services, don't forget to add the trailing . at the end of each record pointing to a Microsoft Server. Otherwise, resolving will incorrectly add your own do  ...
 
Exchange 2013: mailbox database switchover (in a DAG)
edited by on August 12th 2015, at 15:47
In an Exchange cluster with a Database Availability Group (DAG), you can easily "switch over" one, more or all mailbox databases to another node.

Warning
If you need to take a node offline, it's better to put it in maintenance mode. This will properly notify the cluster that the node is in maintenance and prevents automatic failover (of other services, if any) to other nodes.

Switchover can be done through EAC, or through the EMS (Powershell).

To switch over all mailbox databases to a server called EX2:

Move-ActiveMailboxDatabase -Server EX2

To switch over the database called DB1 to a server called EX2:

Move-ActiveMailboxDatabase DB1 -ActivateOnServer EX2

The switchover will  ...
 
Event 1222 when you create a Windows Server 2012 Failover Cluster
edited by on July 17th 2015, at 14:01
When you create a Windows Server 2012 failover cluster, the following event may be logged in the System log:

Event ID 1222 (Microsoft-Windows-FailoverClustering)
The computer object associated with cluster network name resource could not be updated.Unable to protect the Virtual Computer Object (VCO) from accidental deletion.

When a failover cluster or a cluster role is created, a computer account (a so-called Cluster Name Object (CNO)) is created in Active Directory. Since Server 2012, these objects are flagged to prevent accidental deletion. If the main cluster resource (also a computer account) does not have the required permissions on the OU containing the CNOs (by default, this is the   ...
 
SQL Server database stuck in Restoring mode
edited by on July 17th 2015, at 09:15

When restoring a database, you usually start with restoring a full backup, then any differentials, and finally the transaction logs. You set the database restore mode to WITH NORECOVERY, which allows you to perform these additional restores.

But what if you find out that there's nothing more to restore, leaving you with a database stuck in Restoring mode? Then you only need to run a single T-SQL statement:

RESTORE DATABASE [db_name] WITH RECOVERY

Replace db_name with the name of your database.

 
Rolling upgrade scenarios of a SQL Server High-Availability cluster
edited by on July 13th 2015, at 16:16

Follow the chart below to successfully perform a rolling upgrade of your HA SQL Server cluster.

 
No_Sync and No_Light on a SAN FC switch
edited by on July 10th 2015, at 12:35

No_Light means there's no link on the port. Usually this indicates a problem with the physical wiring, either a faulty cable, or the TX/RX have been swapped.

No_Sync means there's a link on the port (so technically, wiring is okay), but there's a problem with the actual communication. The most common problem is a mismatch in speed on the switch port and the HBA on the other side. Your best bet would be to set the port's speed (temporarily) to auto-negotiate and see what speed is selected. If this does not work, try manually setting the port fixed to lower speeds.

 
List of allowed LAN addresses (RFC 1918)
edited by on July 9th 2015, at 10:03

RFC1918 states the following blocks of IPv4 addresses that can be used in a Local Area Network. These are "private" address ranges that do not overlap with public IP addresses.

Network/maskClassFirst usable addr.Last usable addr.
10.0.0.0/8Class A10.0.0.110.255.255.254
172.16.0.0/12Class B (x16)172.16.0.1172.31.255.254
192.168.0.0Class C (x256)192.168.0.1192.168.255.254
 
Recommended placement of FSMO roles on 2 domain controllers
edited by on July 9th 2015, at 09:31

Based on recommendations and best practices from Microsoft, and information I found here, I compiled a FSMO placement scenario for 2 domain controllers:

DC1DC2
PDC Emulator
RID Master
Infrastructure Master		Schema Master
Domain Naming Master
Global Catalog

Also, if your domain is top-level in the AD forest, configure DC1 to sync with external time sources.

 
Remove a node from a Windows 2003 Fail-Over Cluster
edited by on July 8th 2015, at 16:55

To safely remove a node from a Windows 2003 Fail-Over Cluster, follow these steps:

  1. First, using Cluster Administrator, move all roles to the other nodes in the cluster.
    There should be no more roles, including the quorum running on the node.
  2. In Cluster Administrator, right-click the node and click Stop Cluster Service. (Skip this step if it is the last node of the cluster.)
  3. Still in Cluster Administrator, right-click the node and click Evict node. This will remove the node from the cluster.
  4. Optionally, you can now remove the Fail-Over cluster components from the server.
 
Allow a (custom) kext to be loaded by a user (non-root) process on Mac
edited by on July 8th 2015, at 16:36
By default, only processes that are run directly by root are allowed to load kexts. When a user (non-root) process tries to load a kext, an error is logged in system.log similar to:

Request from non-root process 'netbiosd' (euid 222) to load /System/Library/Extensions/smbfs.kext - not allowed.

You can resolve the issue by allowing the specific kext (e.g.: smbfs.kext) to be loaded by non-root processes. This is done by editing the Info.plist file that's included with the kext, usually at /path/to/kext-name.kext/Contents/Info.plist.

Open a Terminal.

Locate the kext and edit its Info.plist file.In our example, this would be the file: /System/Library/Extensions/smbfs.kext/Contents/Info.plist  ...
 
 
showing posts tagged with 'computer'
 
 
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