Squid for Windows and Veeam


Squid for Windows is a free proxy service. What do Squid for Windows and Veeam have to do with each other? Well, I have been on a path to create some guidance on how to harden your Veeam backup infrastructure. The aim of this is to improve your survival chances when your business falls victim to ransomware and other threats. In that context, I use Squid for Windows to help protect the Veeam backup infrastructure which is any of the Veeam roles (VBR Server, proxies, repositories, gateways, etc.). This does not include the actual source servers where the data we protect lives (physical servers, virtual servers or files).

Setting the context

One of the recurring issues I see when trying to secure a Veeam backup infrastructure environment is that there are a lot of dependencies on other services and technologies. There are some potential problems with this. Often these dependencies are not under the control of the people handling the backups. Maybe some counter measures you would like to have in place don’t even exist!

When they do exist, sometimes you cannot get the changes you require made. So for my guidance, I have chosen to implement as much as possible with in box Windows Server roles and features augmented by free 3rd party offerings where required. Other than that we rely on the capabilities of Veeam Backup & Replication. In this process, we avoid taking hard dependencies on any service that we are protecting. This avoids the chicken and egg symptoms when the time to recover arrives.

The benefit of this approach is that we get a reasonably secured Veeam backup infrastructure in place even in a non-permissive environment. It helps with defense in depth if the solutions you deploy are secured well, independent on what is in place or not.

Squid for Windows and Veeam

One of the elements of protecting your Veeam environment is allowing outgoing internet access only to those services required but disallowing access to other all other sites. While the Windows firewall can help you secure your hosts it is not a proxy server. We are also trying to make the Veeam backup infrastructure independent of the environment we are protecting. So we chose not to rely on any exiting proxy services to be in place. If there are that is fine and considered a bonus.

To get a proxy service under our control we implement this with Squid for Windows.

Squid for Windows and Veeam
Install Squid for Windows

You can run this on your jump host, a host holding the Veeam gateway server role or, depending on your deployment size a dedicated virtual machine. You can also opt to have a dedicated second NIC on a separate Subnet/network to provide internet access. We will then point all Veeam backup infrastructure servers their proxy settings the Squid Proxy.

Squid white listing

In Squid, we can add a white list with sites we want to allow access to over HTTPS and block all others. In my Veeam labs, I allow sites associated with DUO (MFA), Wasabi (budget-friendly S3 compatible cloud storage), Veeam.com, and a bunch of Microsoft Sites associated with Windows update. Basically, this is a text file where you list the allowed sites. Mine is calles Allowed_Sites.txt and I store it under C:\Program Files\Squid\etc\squid.

## These are websites needed to keep the Veeam backup infra servers
## up to date and functioning well. They also include the sites needed
## by 3rd party offerings we rely on such as DUO, WASABI, CRL sites.
## Add .amazonaws.com, Azure storage as required



#Windows Update



MFA providers and internet access

Warning! When leveraging MFA like DUO it is paramount that you add .duosecurity.com to the list of allowed sites. If not the DUO client cannot work properly. You will see errors like “The Duo authentication returned an unexpected response”.

You will have to fix this. As the server cannot contact the DUO service while it knows internet access is available, so the offline MFA access won’t kick in.

Use the Squid log

The Squid log lists all allowed and denied connections, you can quickly find out what is missing in the white list and add it.

Looking at this log while observing application behavior helps create a complete white list that only contains the FQDNs needed.

To make this work we first need to configure our Squid service to use the white list file. Below I have listed my configuration (C:\Program Files\Squid\etc\squid\squid.conf in the Veeam lab.

Veeam Squid Configuration

# Recommended minimum configuration:

# Example rule allowing access from your local networks.
# Adapt to list your (internal) IP networks from where browsing
# should be allowed

acl localnet src	# RFC1918 possible internal network

acl SSL_ports port 443
acl Safe_ports port 80		# http
acl Safe_ports port 443		# https

## Custom ACL

# Recommended minimum Access Permission configuration:

# Deny requests to certain unsafe ports
http_access deny !Safe_ports

# Deny CONNECT to other than secure SSL ports
http_access deny CONNECT !SSL_ports

# Only allow cachemgr access from localhost
http_access allow localhost manager
http_access deny manager

# We strongly recommend the following be uncommented to protect innocent
# web applications running on the proxy server who think the only
# one who can access services on "localhost" is a local user
http_access deny to_localhost

acl allowed_sites dstdomain '/etc/squid/allowed_sites.txt'
http_access deny !allowed_sites
http_access allow CONNECT allowed_sites

# Example rule allowing access from your local networks.
# Adapt localnet in the ACL section to list your (internal) IP networks
# from where browsing should be allowed
http_access allow localnet
http_access allow localhost

# And finally deny all other access to this proxy
http_access deny all

# Squid normally listens to port 3128
http_port 3128

# Uncomment the line below to enable disk caching - path format is /cygdrive/<full path to cache folder>, i.e.
#cache_dir aufs /cygdrive/d/squid/cache 3000 16 256

# Leave coredumps in the first cache dir
coredump_dir /var/cache/squid

# Add any of your own refresh_pattern entries above these.
refresh_pattern ^ftp:		1440	20%	10080
refresh_pattern ^gopher:	1440	0%	1440
refresh_pattern -i (/cgi-bin/|\?) 0	0%	0
refresh_pattern .		0	20%	4320


max_filedescriptors 3200

To force the use of the proxy, you can block HTTP/HTTPS for the well-known internet ports such as 80, 8080, 443, 20, 21, etc. in the Windows firewall on the Veeam backup infrastructure hosts. Because the Veeam admins have local admin rights, which means they can change configuration settings. That requires intentional action. If you want to prevent internet access at another level, your security setup will need an extra external firewall component out of reach of the Veeam admins. It can be an existing FW or a designated one that allows only the proxy IP to access the internet. That’s all fine, and I consider that a bonus which definitely provides a more complete solution. But remember, we are trying to do everything here as much in-box to avoid dependencies on what we might not control.

Getting the proxy to be used

Getting the proxy to work for Veeam takes some extra configuration. Remember that there are 3 ways of setting proxy configurations in Windows. I have discussed this in my blog Configure WinINET proxy server with PowerShell.. Please go there for that info. For the Veeam services we need to leverage the WinHTTP library, not WinINET.

If the proxy is not set correctly and/or you have blocked direct internet access you will have issues with retrieving cloud tier certificates and Automatic license update fails when HTTP proxy is used or errors retrieving the certificates for your cloud capacity tier. All sorts of issues you do not want to happen.

We can set the WinHTTP proxy as follows with PowerShell / Netsh

$ProxyServer = ""
$ProxyBypassList = ";;;;<local>"  
netsh winhttp set proxy $ProxyServer bypass-list=$ProxyBypassList

If you want to get rid of the WinHTTP proxy setting you can do so via

netsh winhttp reset proxy

The proxy setting you do for WinINET with the Windows GUI or Internet Explorer are not those for WinHTTP. Edge Chromium actually takes you to the Windows proxy settings, there is no separate Edge GUI for that. But, again, That is WinINET, not Win HTTP.

You can set the WinINET proxy per user or per machine. This is actually a bit less elegant than I would like it to be. Also, remember that a browser’s proxy settings can override the system proxy settings. If you have set the system proxy settings (Windows or Internet Explorer) you can import it into WinHTTP via the following command.

netsh winhttp import proxy source=ie

Having WinINET configured for your proxy might also be desirable. If you set it I suggest you do this per machine and avoid users from changing this. Now, the users will be limited to a small number of Veeam admins. If you want to automate it, I have some more information and some PowerShell to share with you in Configure WinINET proxy server with PowerShell.


For our purposes, we used Squid as a free proxy, which we can control our selves. It is free and easy to setup. It prevents unintentional access and surfing to the internet. Sure, it can easily be circumvented by an administrator on a Veeam host, if no other countermeasures are in effect. But it serves its purpose of not allowing internet connections to anywhere by default. In that respect, it is an aid in maintaining a more secure posture in the daily operations of the Veeam backup infrastructure.

Veeam File Share backups and knowledge worker data


Today I focus on Veeam File Share backups and knowledge worker data testing. In Veeam NAS and File Share Backups did my 1st testing with the RTM bits of Veeam Backup & Replication V10 File Share backup options. Those tests were focused on a pain point I encounter often in environments with lots of large files: being able to back them up at all! Some examples are medical imaging, insurance, and GIS, remote imaging (satellite images, Aerial photography, LIDAR, Mobile mapping, …).

The amount of data created has skyrocketed driven by not only need but the advances in technology. These technologies deliver ever-better quality images, are more and more affordable, and are ever more applicable in an expanding variety of business cases. This means such data is an important use case. Anyway for those use cases, things are looking good.

But what about Veeam File Share backups and knowledge worker data? Those millions of files in hundreds of thousands of folders. Well, in this blog post I share some results of testing with that data.

Veeam File Share backups and knowledge worker data

For this test we use a 2 TB volume with 1.87TB of knowledge worker data. This resides on a 2 TB LUN, formatted with NTFS and a unit allocation size of 4K.

1.87 TB of knowlegde worker dataon NTFS

The data consists of 2,637,652 files in almost 196,420 folders. The content is real-life accumulated data over many years. It contains a wide variety of file types such as office, text, zip, image, .pdf, .dbf, movie, etc. files of various sizes. This data was not generated artificially. All servers are Windows Server 2019. The backup repository was formatted with ReFS (64K allocation unit size).

Backup test

We back it up with the file server object from an all-flash source to an all-flash target. There is a dedicated 10Gbps backup network in the lab. As we did not have a separate spare lab node we configured the cache on local SSD on the repository. I set the backup I/O control for faster backup. We wanted to see what we could get out of this setup.

Below are the results.

Veeam File Share backups and knowledge worker data
45:28 minutes to backup 1.87 TB of knowledge worker data. I like it.

If you look at the back-up image above you see that the source was the bottleneck. As we are going for maximum speed we are hammering the CPU cores quite a bit. The screenshot below makes this crystal clear.

We have plenty of CPU cores in the lab on our backup source and we put them to work.
The CPU core load on the backup target is far less.

This begs the question if using the file share option would not be a better choice. We can then leverage SMB Direct. This could help save CPU cycles. With SMB Multichannel we can leverage two 10Gbps NICs. So We will repeat this test with the same data. Once with a file share on a stand-alone file server and once with a high available general-purpose file share with continuous availability turned on. This will allow us to compare the File Server versus File Share approach. Continuous availability has an impact on performance and I would also like to see how profound that is with backups. But all that will be for a future blog post.

Restore test

The ability to restore data fast is paramount. It is even mission-critical in certain scenarios. Medical images needed for consultations and (surgical) procedures for example.

So we also put this to the test. Note that we chose to restore all data to a new LUN. This is to mimic the catastrophical loss of the orginal LUN and a recovery to a new one.

The restore takes longer than the backup for the same amount of data, the restore speed is typically slower for large amounts of smaller files.

Below you will find a screenshot from the task manager on both the repository as well as the file server during the restore.

The repository server from where we are restoring the data
The file server where the backup is being restored completely on a new LUN. Note the peak throughput of 6.4 Gbps.

Mind you, this varies a lot and when it hits small files the throughput slows down while the cores load rises

The file server during the restore is having to work the hardest when it has to deal with the least efficient files.


For now, with variable data and lots of small files, it looks that restores take 2.5 to 3 times as long as backups with office worker data. We’ll do more testing with different data. With large image files, the difference is a lot less from our early testing. For now, this gives you a first look at our results with Veeam File Share backups and knowledge worker data As always, test for your self and test multiple scenarios. Your mileage will vary and you have to do your own due diligence. These lab tests are the beginning of mine, just to get a feel for what I can achieve. If you want to learn more about Veeam Backup & Replication go here.Thank you for reading.

Hyper-V Amigos Showcast Episode 20 and 21


This is just a quick blog post to let you know the Hyper-V Amigos have released 2 webcasts recently. These are Hyper-V Amigos Showcast Episode 20 and 21. You will find a link to the videos and a description of the content below.

Hyper-V Amigos Showcast – Episode 20

In episode 20 of the Hyper-V Amigo ShowCast, we continue our journey in the different ways in which we can use storage spaces in backup targets. In our previous “Hyper-V Amigos ShowCast (Episode 19)– Windows Server 2019 as Veeam Backup Target Part I” we looked at stand-alone or member servers with Storage Spaces. With both direct-attached storage and SMB files shares as backup targets. We also played with Multi Resilient Volumes.

For this webcast, we have one 2 node S2D cluster set up for the Hyper-V workload (Azure Stack HCI). On a second 2 node S2D cluster, we host 2 SOFS file shares. Each on their own CSV LUN. SOFS on S2D is supported for backups and archival workloads. And as it is SMB3 and we have RDMA capable NICs we can leverage RDMA (RoCE, Mellanox ConnectX-5) to benefit from CPU offloading and superb throughput at ultra-low latency.

Hyper-V Amigos Show Cast Episode 20

Some extra information

The General Purpose File Server (GPFS role) is not supported on S2D for now. You can use GPFS with shared storage and in combination with continuous availability. This performs well as a high available backup target as well. The benefit here is that this is cost-effective (Windows Server Standard licenses will do) and you get to use the shared storage of your choice. But in this show cast, we focus on the S2D scenario and we didn’t build a non-supported scenario.

You would normally expect to notice the performance impact of continuous availability when you compare the speeds with the previous episode where we used a non-high available file share (no continuous availability possible). But we have better storage in the lab for this test, the source system is usually the bottleneck and as such our results were pretty awesome.

The lab has 4 Tarox server nodes with a mix of Intel Optane DC Memory (Persistent Memory or Storage Class Memory), Intel NVMe and Intel SSD disks. For the networking, we leverage Mellanox ConnectX-5 100Gbps NICs and SN2100 100Gbps switches. Hence we both had a grin on our face just prepping this lab.

As a side note, the performance impact of continuous availability and write-through is expected. I have written about it before here. The reason why you might contemplate to use it. Next to a requirement for high availability, is due to the small but realistic data corruption risk you have with not continuously available SMB shares. The reason is that they do not provide write-through for guaranteed data persistence.

We also demonstrate the “Instant Recovery” capability of Veeam to make workloads available fast and point out the benefits.

Hyper-V Amigos Showcast – Episode 21

In episode 21 we are diving into leveraging the Veeam Agent for Windows integrated with Veeam Backup & Replication (v10 RC1)  to protect our physical S2D nodes. For shops that don’t have an automated cluster node build processes set up or rely on external help to come in and do it this can be a huge time saver.

We walk through the entire process and end up doing a bare metal recovery of one of the S2D nodes. The steps include:

  • Setting up an Active Directory protection group for our S2D cluster.
  • Creating a backup job for a Windows Server, where we select failover cluster as type (Which has only the “Managed by Backup Server”  as the mode).
  • We run a backup
  • After that, we create the Veeam Agent Recovery Media (the most finicky part)
  • Finally, we restore one of the S2D hosts completely using the bare metal recovery option

Some more information

Now we had some issues in the lab one of them suffering to a BSOD on the laptop used to make the recording and being a bit too impatient when booting from the ISO over a BMC virtual CD/DVD. Hence we had to glue some parts together and fast forward through the boring bits. We do appreciate that watching a system bot for 10 minutes doesn’t make for good infotainment. Other than that, it went fine and we were able to demonstrate the process from the beginning to the end.

As is the case with any process you should test and experiment to make sure you are familiar with the process. That makes it all a little easier and hurt a little less when the day comes you have to do it for real.

We hope the show cast helps you look into some of the capabilities and options you have with Veeam in regards to protecting any workloads. Long gone are the days that Veeam was only about protecting virtual Machines. Veeam is about protecting data where ever it lives. In VMs, physical servers, workstations, PCs, laptop, on-prem, in the cloud and Office 365. On top of that, you can restore it where ever you want to avoid lock-in and costly migration projects and tools. Check it out.


We will be doing more web casts on Veeam Backup & Replication v10 in 2020 as it will be generally available in Q1 as far I can guess.

Hyper-V Amigos Showcast Episode 20 and 21

But with Hyper-V Amigos Showcast Episode 20 and 21, that’s it for 2019. Enjoy the holidays during this festive season. The Hyper-V Amigos wish you a Merry X-Mas and a very happy New Year in 2020!

Veeam Vanguard Renewals and Nominations 2020


Are you are working with Veeam software solutions? Are you passionate about sharing your experiences, knowledge, and insights? If so, you might want to consider a nomination for the Veeam Vanguard program. If you are already a Veeam Vanguard I’m pretty sure you already know submissions for Veeam Vanguard Renewals and Nominations 2020 are open.

Veeam Vanguard Renewals and Nominations

As we are nearing the end of 2019 Veeeam has opened the Veeam Vanguard Renewals and Nominations for 2020.

Describing the Veeam Vanguard program is not easily done. But Nikola Pejková has done a great job to do exactly that in Join the Veeam Vanguard 2020 class! She also explains how to nominate someone or yourself. Read the blog post and find out if this is something for you. I enjoy being a part of it because I get to learn with and from some of the best minds in the industry. This allows me to help others better while also keeping up with the changing IT landscape whilst helping others.

Veeam Vanguard Renewals and Nominations 2020
My fellow Veeam Vanguard and me in a Q&A session with the Veeam R&D and PM teams at the Veeam Vanguard Summit.

I would like to emphasize that the diversity of the Veeam Vanguard is paramount to me. It works because we have people in there form around the globe, from all kinds of backgrounds and job roles. This helps open up discussions with different points of view and experiences. Customers, consultants, and partners look at needs and solutions from their perspectives. Having us together in the Vanguard benefits us all and prevents tunnel vision.

Nominate someone, yourself or be nominated

Nikola explains how to do this in her blog so read Join the Veeam Vanguard 2020 class! and apply to become Vanguard! It is quite an experience. Quality people who are active in the commumnity and help by sharing their knowledge are welcomed and appreciated. Maybe you’ll find yourself to be a Veeam Vanguard in 2020!