Posts

The one stop solution for backup and DR: Vembu BDR Suite

I have worked with a lot of backup software products during my career, but for the last years I have primarily worked with MicroFocus Data Protector (former HP OmniBack, HP Data Protector, or HPE Data Protector), and Veeam Backup & Replication. Data Protector was a great solution for traditional server environments, or when UNIX (HP-UX, AIX, Solaris etc.) compatibility was required. Features like Zero Downtime Backups, LAN-free or Direct SAN backups were available for many years. But their code quality has suffered severely in the recent years. The product no longer seemed like a one-stop shop. Some months ago, HPE sold its software division to MicroFocus and started to sell Veeam Backup & Replication through its channel. Some months prior selling the complete software division, HPE acquired Trilead, which is many of us well known because of their VM Explorer. Sad but true: Data Protector is dead to me.

CloudFlare API v4 and Fail2ban: Fixing the unban action

In January 2017, I wrote an article about how to protect your Wordpress blog using the WP Fail2Ban plugin, fail2ban on your Linux/ FreeBSD host, and CloudFlare. Back then, the fail2ban was using the CloudFlare API V1, which was already deprecated since November 2016.

Although the actions were updated later to use CloudFlare API V4, I still had problems with the unbaning of IP addresses. IP addresses were banned, but the unban action failed. 

Windows Network Policy Server (NPS) server won't log failed login attempts

This is just a short, but interesting blog post. When you have to troubleshoot authentication failures in a network that uses Windows Network Policy Server (NPS), the Windows event log is absolutely indispensable. The event log offers everything you need. The success and failure event log entries include all necessary information to get you back on track. If failure events would be logged…

Today, I was playing with Alcatel-Lucent Enterprise OmniSwitches and Access Guardian in my lab. Access Guardian refers to the some OmniSwitch security functions that work together to provide a dynamic, proactive network security solution:

Replace SSL certificates on Citrix NetScaler using the CLI

Sometimes you have to replace SSL certificates instead of updating them, e.g. if you switch from a web server SSL certificate to a wildcard certificate. The latter was my job today. In my case, the SSL certificate was used in a Microsoft Exchange 2016 deployment, and the NetScaler configuration was using multiple virtual servers. I’m using this little script for my NetScaler/ Exchange deployments.

When using multiple virtual servers, replacing a SSL certificate using the GUI can be challenging, because you have to navigate multiple sites, click here, click there etc. Using the CLI, the same task is much easier und faster. I like the Lean mindset, so I’m trying to avoid “waste”, in this case, “waste of time”.

Bypass stateful firewall on a Sophos XG

Usually, bypassing a firewall is not the best idea. But sometimes you have to. One case, where you want to bypass a firewall, is asymmetric routing.

What is asymmetric routing? Imagine a scenario with two routers on the same network. One router offeres access to the internet, the other router provides access to other sites with site-2-site VPN tunnels.

Patrick Terlisten/ vcloudnine.de/ Creative Commons CC0

Patrick Terlisten/ vcloudnine.de/ Creative Commons CC0

Veeam backups fails because of time differences

Last week I had an interesting incident at a customer. The customer reported that one of multiple Veeam backup jobs jobs constantly failed.

The backup job included two VMs, and the backup of one of these VMs failed with this error:

Error: Failed to open VDDK disk [[VMDS-SAS-01] VMDC1/VMDC1_1.vmdk] ( is read-only mode - [true] ) 
Failed to open virtual disk Logon attempt with parameters [VC/ESX: [vcenter.domain.tld];Port: 443;Login: 
[ADAdministrator];VMX Spec: [moref=vm-59];Snapshot mor: [snapshot-20226];Transports: [san];Read Only: [true]]
failed because of the following errors: Failed to open virtual disk Logon attempt with parameters 
VC/ESX: [vcenter.domain.tld];Port: 443;Login: [AD\Administrator

The verified the used credentials for that job, but re-entering the password does not solved the issue. I then checked the Veeam backup logs located under %ProgramData%\VeeamBackup (look for the Agent.Job_Name.Source.VM_Name.vmdk.log) and found VDDK Error 3014:

DOT1X authentication failed on HPE OfficeConnect 1920 switches

The last two days, I have supported a customer during the implementation of 802.1x. His network consisted of HPE/ Aruba and some HPE Comware switches. Two RADIUS server with appropriate policies was already in place. The configuration and test with the ProVision based switches was pretty simple. The Comware based switches, in this case OfficeConnect 1920, made me more headache.

The customer had already mac authentication running, so all I had to do, was to enable 802.1x on the desired ports of the OfficeConnect 1920. The laptop, which I used to test the connection, was already configured and worked flawless if I plugged it into a 802.1x enabled port on a ProVision based switch. The OfficeConnect 1920 simply wrote a failure to its log and the authentication failed. The RADIUS server does not logged any failure, so I was quite sure, that the switch caused the problem.

HPE Networking expert level certifications

A couple of days ago, I took the HP0-Y47 exam “Deploying HP FlexNetwork Core Technologies”. It was one of two required exams to achive the HPE ASE - Data Center Network Integrator V1, and the HP ASE - FlexNetwork Integrator V1 certification. It was a long planned upgrade to my HP ATP certification, and it is a necessary certification for the HPE partner status of my employer.

You might find it confusing that I’m talking about an HP ASE and a HPE ASE. That is not a typo. The HP ASE was released prior the HP/ HPE split. The HPE ASE was released after the split in HP and HPE.

vSphere Distributed Switch health check fails on HPE Comware switches

During the replacement of some VMware ESXi hosts at a customer, I discovered a recurrent failure of the vSphere Distributed Switch health checks. A VLAN and MTU mismatch was reported. On the physical side, the ESXi hosts were connected to two HPE 5820 switches, that were configured as an IRF stack. Inside the VMware bubble, the hosts were sharing a vSphere Distributed Switch.

The switch ports of the old ESXi hosts were configured as Hybrid ports. The switch ports of the new hosts were configured as Trunk ports, to streamline the switch and port configuration.

Demystifying "Interfaces on which heartbeats are not seen"

By accident, I found a heartbeat/ VLAN issue on a NetScaler cluster at one of my customers. The NetScaler ADC appliances have three interfaces connected to a switch stack. Two of the three interfaces were configured as a channel (LAG). This is a snippet from the config:

set channel LA/1 -tagall ON -throughput 0 -lrMinThroughput 0 -bandwidthHigh 0 -bandwidthNormal 0
...
bind vlan 10 -ifnum 1/3
bind vlan 10 -ifnum LA/1 -tagged
bind vlan 54 -ifnum LA/1 -tagged
bind vlan 55 -ifnum LA/1 -tagged

On the switch stack, the port to which interface 1/3 is connected, is configured as an access port. The ports, to which the channel is connected, is configured as a trunk port with some permitted VLANs. The customer is using HPE Comware based switches. The terminology is the same for Cisco. If you use HPE ProVision or Alcatel Lucent Enterprise, translate “access” to “untagged” and “trunk” to “tagged”. Because the channel is configured as a trunk port on the switch, the tagall option was set.