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showing posts of September 2019
 
by lunarg 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  ...
by lunarg on September 9th 2019, at 16:54
On VCSA, the database is stored on a separate disk. It could happen that this disk runs out of room, causing Vcenter to no longer function properly. One way to resolve this is by running database clean up as mentioned in KB 2110031. However, if this is not possible, or you don't want to clear out the data, you can also resize the disk.

For this to work, you'll need root access and access to the bash-shell, either on the console or through SSH.

Before resizing, identify the physical disk to be resized. For VCSA 6.5 and 6.7, this should normally be Disk 8 (device node in linux = /dev/sdh), but your setup may vary, so it's best to double-check this.

In VCSA 6.5 and 6.7, the database is locat  ...
by lunarg on September 9th 2019, at 12:45
Handling snapshots (creating, deleting, restoring) is rather intuitive when you already have some experience with PowerCLI. As a reference, here are some one-liners. As always with Powershell, there's more than one way to achieve a goal... The examples used here assume a VM named "SRV01". Adjust as needed.

Create a snapshot:

Get-VM SRV01 | New-Snapshot -Name "My snapshot"

Remove all snapshots (disabling confirmation request in the process):

Get-VM SRV01 | Get-Snapshot | Remove-Snapshot -Confirm:$false

To handle a specific snapshot, you could do something like this:

$vm = Get-VM SRV01$snap = Get-Snapshot -VM $vm -Name "My snapshot"# do something with the sn  ...
by lunarg on September 5th 2019, at 16:43
For users which really want to prevent Windows 10 from automatically installing updates, here are some methods to disable automatic updates. Depending on which method you use, you will still be able to manually check and install updates, or not be able to install updates at all...

Note that the methods leverage group policies, which is not supported on Windows 10 "Home/Essential" editions. A minimum of Windows 10 Pro or better is needed.

Caution
It is generally not recommended to disable automatic updates. Doing so (and not subsequently regularly installing the updates yourself) increases the risk of data loss and/or stealing due to potentional vulnerabilities in Windows 10.

The  ...
 
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