Azure Site to Site VPN Blocking Some Traffic

Published On: 2020-10-19By:

I ran across an interesting a couple of weeks ago when working with a client. The client has several subsidiaries each with their own vNet. The client had a site to site VPN been the Azure vNets. All traffic was successfully crossing the Azure Site to Site VPN as expected. The sticking point was that a software licensing server running in one of the subsidiaries Azure infrastructure configurations. The software licensing software simply wasn’t working.

We fired up Wireshark on Azure VM which was running the software as well on the Azure VM which was running the licensing software. In Wireshark on the VM running the software, we could see the software trying to talk to the licensing software. On the licensing server, we could see the connection request come in, and we could see the response from the licensing software going back to the client. But we looked on the VM running the software we couldn’t see the packet coming back from the licensing server. So the network traffic was simply getting blocked, somewhere. We didn’t have any network security groups set up, and we didn’t have any software firewalls in place. So nothing should be blocking traffic.

We looked at the response that was coming from the licensing server, and it had the DoNotFragment bit set on the response network packet. Now the sure weird thing is that the packet was only 1430ish bytes in size. So it would have fit within the 1500 byte packet, so there was zero chance of the packet being fragmented. But the bit was being set within the vendor’s software, so we didn’t have any way to remove that flag.

We were able to fix it, by changing from a Site to Site VPN to a peered network connection between the two vNets. Changing the network connection to a peer allowed the software licensing process to work as expected and solved the problem.

So if you have software which requires the DoNotFragment bit in your connection, then an Azure Site to Site VPN isn’t going to work for you. If you are doing everything in Azure a peer can work while a Site to Site VPN doesn’t work.


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5 Steps to Make WordPress Faster

Published On: 2020-10-12By:

If you’ve been working with WordPress for a while now, you know that it’s a pretty solid platform for blogging, posting content.

However, the WordPress database was clearly made by developers and there wasn’t a DBA involved. And this isn’t just WordPress, but this goes for some of the plugins as well.

I’ve got Query Monitor installed on our WordPress installation, and it pops up with slow queries every once and a while. So I figured that I’d look at the queries, and look at the indexes on the database and see what I can do about this.

Needless to say, there’s a few indexes that needed to be added.

I’m assuming that you are using the prefix wp_ on all your tables, which is the default. If you are using a prefix other than this, you’ll need to adjust this index creation scripts.

The first one is against the wp_options table.

create index dcac_option_name_autoload on wp_options (option_name, autoload);

The next one to create is against wp_term_taxonomy.

create index dcac_taxonomy on wp_term_taxonomy (taxonomy, term_taxonomy_id, term_id, parent, count, description(400));

The third index to be created against one of the WordPress tables is against the wp_terms table.

create index dcac_name on wp_terms (name, term_id, slug, term_group, term_order);

The fourth index and fifth indexes that I’ve found that you need to create are actually against one of the Yoast plugin tables, but since most people have the Yoast plugin installed, you’ll want this index as well.

create index dcac_id_permalink_update_at on wp_yoast_indexable (id,  permalink(10), updated_at);
create index dcac_object_type on wp_yoast_indexable (object_type, object_sub_type);

These indexes should help your WordPress system work more efficiently as it will be easier for the MySQL database that is behind your WordPress database to be able to find the data that it needs to in order to run your website.

None of these indexes are going to shave seconds on your page load times, but if they each save 100-200 milliseconds off your page load time, that’s close to a second total, and that’s a decent amount of time for queries that happen on each page load.

As I run across more indexes that need to be created, I’ll post them as I can.

If you aren’t sure how to run MySQL scripts against your database, there’s a variety of ways so if you aren’t sure how to run SQL scripts against your WordPress database, check with your hosting provider.

Looking to move your WordPress website to Microsoft Azure? The team at DCAC can help you migrate to a Cloud Services solution.


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UniFi Routers, VMware vSphere and vLAN Fun

Published On: 2020-10-05By:

Recently we upgraded the networking in our CoLo from our existing horrible, not all the features work correctly, bought off eBay NetGear switches to a brand new (actually purchased new) Ubiquiti network stack. We went with Ubiquiti because they have a really good reputation, they have a fantastic price point, and the UI is really simple to use while giving us all of the features that we were looking for.

Like any good IT deployment, we hit a snag when we were pushing out out network configuration. All of our servers have 10 Gig network cards in them, and our SAN also has 10 Gig network cards for our NFS shares (we are a VMware vSphere shop), so we have a storage network. We also wanted to put our VMs on the 10 Gig cards, as they were on 1 Gig ports before and we wanted them to have more bandwidth available to them.

In the UniFi software on the Ubiquiti equipment has two different networking setups. The base network which we setup as our management network. Then any other subsets that need to be setup are configured, but they require a VLAN to be configured. We had a few networks to setup, and those were our Infrastructure network which we gave a VLAN of 4 to, our Storage network which we gave a VLAN of 5 to, and our lab which we gave a VLAN of 100 to.

Our VMware servers all have a dedicated NIC which we are using for our Management ports, so we didn’t need to have the Management network be accessible from the NIC that the VMs were going to use. Within the UniFi software I created was is called a port profile which can contain a variety of subnets. This way a single switch port can be on multiple subnets, which was exactly what I wanted. I wanted the 10 Gig ports and their NICs to be on the Storage, Infrastructure, and Lab networks. So I created a single port profile with all of these subnets in it. As you can see from the screenshot below, when you do this you select a netive network for the port profile.

After I got this setup, I was getting weird responses from the VMs and the VMware hosts that were trying to talk to the storage. I put VLAN Ids in VMware or all these networks as well, but things still working talking correctly.

It turns out, that whatever network you have configured as the native network, within VMware this means that you don’t put a VLAN ID for it. So in my case the storage network within VMware does not get a VLAN ID, while the other networks do; even through the storage network has a VLAN ID of 5 within the UniFi OS.

Once I did that, the storage for the VMs was able to talk perfectly and all the VM Subnets worked as expected.


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Modern Database Performance Tuning Methods

Published On: 2020-09-28By:

On Thursday, October 15th, 2020 at 11am Pacific / 2pm Eastern / 6pm UTC Thomas LaRock and Denny Cherry will be presenting a live webcast on to walk you through a variety of performance tuning methods, which ones are right for you and your systems, and how to know when to call for help.

We encourage everyone that works with a SQL Server database system to join us on this webcast by signing up for it today and we’ll see you on October 15.


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