Oct 122018
 
DNS

In the perfect and properly configured world, every internet user has a reverse DNS entry. This is is the DNS entry which tells people, servers, and services, what any given IP’s hostname is. Also, again in the perfect world, web servers shouldn’t check these, as the DNS query itself usually has to complete before it starts serving website data.

One of the key way’s webmasters and web server administrators increase their web server response times, is to make sure that their server is NOT performing reverse DNS queries when serving the site. However, we aren’t in a perfect world, and many web servers and web sites still perform these queries.

Many web servers do these queries because they are using mis-configured statistic generation software (website stats), default web server configuration files, or other reasons.

The problem

I recently had a discussion with a fellow IT professional where they were having issues with load times when opening websites. They were on a high speed business internet connection, so they figured it had to do with something else. They said they checked absolutely everything, so I decided to see what I could do to help out!

In my own research I noticed that on my own web server (which doesn’t perform reverse DNS queries on users), that numerous visitors both local to North America and abroad, did not actually have properly configured reverse DNS entries. One can deduce that when one of these users visits a website that actually performs an RDNS check during initial connection, it could cause a delay while the server itself waits for the DNS query to be performed (or even worse, timeout).

When further investigating, I also noticed a trend that the larger the company and the more expensive the internet connection, the more IPs that did not have reverse DNS records. I also noticed the IP addresses provided to my colleague did not have RDNS records.

I relayed this information back to my colleague and after they created the proper reverse DNS records, it seemed to help the issue!

Final Note

Since I don’t have direct access to their network, I couldn’t confirm this was the actual issue, or the only issue, but this just goes to show that you should always have your networks (both internal and external) properly configured using leading practices. In the long run, it saves time and avoids issues.

Sep 072018
 
DNS

If you’re experiencing DNS issues (or internet issues) today on September 7 2018, you’re not alone. As of this morning, I’ve been noticing increased traffic coming in to my blog from people searching for DNS issues.

I decided to do a little investigation and noticed numerous people reporting DNS issues in Canada and the United States. While this is being reported by users across North America, I’ve been noticing a trend reporting issues that may be using Canadian hosted DNS Servers.

I will be updating this post below as I find out more information. If you know anything or can contribute any information, please leave a comment below.

Aug 202018
 

An all too common problem is when users report e-mail delays ranging from 5 to 15 minutes. When troubleshing these types of issues, you’ll notice this commonly occurs when receiving e-mails from organizations that use Office 365. Specifically this occurs due to greylisting.

Why does this happen

You’re organization is using greylisting on your e-mail proxy/SMTP relay to reduce spam. Greylisting temporarily rejects the first send of an e-mail and waits for the sending server to re-transmit the message. This process usually takes around 5-15 minutes to complete. Greylisting is used because spammers won’t re-transmit the message, which leads to a massive reduction of spam messages coming through.

Once the sending server retransmits, the sending server IP address is added to your firewalls “safe senders” whitelist. From this point on the IP address (or server) will not be subject to greylisting (and any subsequent e-mails).

Office 365 has hundreds, if not thousands (possibly 10’s of thousands) of servers they use to transmit e-mail. The chance of multiple e-mails being sent from a single server is very slim, therefor greylisting is applied to every IP (server) that is sending e-mail because it’s different. Each e-mail from an Office 365 user can take 5-15 minutes, since a new server is used every time.

How to resolve

You’ll need to configure and add an exception to your e-mail proxy/SMTP relay/firewall. This exception can be based off domain, DNS name of sending server, or IP address ranges.

Scroll down for instructions on how to create an exception on a Sophos UTM.

Domain Exception

If you use domain based exceptions, you’ll need to configure these manually for each sending domain that you want your firewall to skip greylist checking. This is a very manual process, which requires lots of human intervention to continuously update your greylist exception.

DNS FQDN of MX Server

This method is the easiest, however most firewall or UTM’s will now allow these types of exceptions since a number of DNS queries will be needed everytime an e-mail comes in. One DNS query on the MX record, and then another DNS query on the DNS host contained in the MX record. If you can configure this type of exception, you’ll want to configure it as below:

*-com.mail.protection.outlook.com

IP Address Range

This is the best method. To create an IP address range exception, we’ll need a copy of all the IP address ranges or IP address spaces that Office 365 uses to send mail. This list can be found at: https://docs.microsoft.com/en-us/office365/SecurityCompliance/eop/exchange-online-protection-ip-addresses.

We’ll need to create an exception that skips greylist checking on the IP addresses outlined in the above link. This will stop any greylist checking on e-mails from Office 365 servers.

In my case, I use a Sophos UTM firewall, and to create an exception I had to do the following:

  1. Log on to the Webmin interface.
  2. Select “Email Protection”, then “STMP” on the left hand side, then “Exceptions” tab at the top.

    Sophos UTM E-Mail and SMTP Exception List

    Sophos UTM E-Mail and SMTP Exception List

  3. Create a “New Exception List” and call it “Office 365 GreylistWhitelist”.
  4. Check the “Greylisting” box under “Antispam”, and then check the “For these source hosts/networks”.

    Sophos UTM SMTP Create Exception

    Sophos UTM SMTP Create Exception

  5. Click the “+” button, and call the Network Definition “Exchange365-EOP-Group”. Change the type to “Network Group”.
  6. Click the “+” button in the members section, and start adding the IP spaces. Repeat this for each IP space (in total I added 23). Each network name (IP address space) requires a unique name, I named mine “Exchange365-EOP1” through “Exchange365-EOP23”.

    Sophos UTM SMTP Configure Exception

    Sophos UTM SMTP Configure Exception

  7. Click Save on the Network Group, and click Save on the exception.
  8. Enable the Exception

    Sophos UTM SMTP Exception Rule

    Sophos UTM SMTP Exception Rule

  9. Completed! You’ve now made the exception and delays should no longer occur.
May 062018
 
Sophos XG and Sophos UTM

Today I’m going to be talking about connecting a Sophos XG firewall to a Sophos UTM firewall for a site-to-site VPN connection specifically using SSL tunneling. Furthermore we are doing this to connect a Microsoft Azure Virtual Network (using a Sophos XG instance) to an On-Premise LAN (running a Sophos UTM).

This type of connection and configuration is standard for corporations, businesses, and organizations who have workloads on Microsoft Azure and need to connect their Azure environment to their corporate LAN. To learn how to deploy Sophos XG in Microsoft Azure, please read this post.

WARNING AND DISCLAIMER: Following the steps in this document if done incorrectly or if your environment is different from the one used in this example, can cause network connectivity issues or a loss of connectivity. An assumption is made that you are skillful enough to know what tasks you are performing and what result they may have on your own environment. You may need to revert these steps if connectivity is lost to restore access to your environment.

Let’s ask some key questions and get some answers:

  • Why are we using both (2) products, Sophos XG and Sophos UTM for the connection instead of using the same product on each end?
    • Sophos only supports deployment of the Sophos XG on Microsoft Azure. Sophos UTM cannot be deployed on Azure. Numerous companies and organizations are still using the Sophos UTM product for their on-premise IT infrastructure. There is a need to have these different products co-exist and function together, like in this specific example.
  • Why are we using a Sophos XG Appliance/Instance to handle the VPN on Microsoft Azure, instead of using the Microsoft branded Azure VPN Gateway?
    • Microsoft Azure has a VPN gateway appliance which can handle the Azure side of the VPN connection, however this is a resource that costs money (instance time and instance data transfer) and has limited configuration options. Numerous companies and organizations are using Sophos XG instances on Azure to protect their internet facing workloads already. Instead of paying for 2 resources (Sophos XG and Microsoft VPN Gateway), you can consolidate and use one for both. You also have extra functionality and security options when using the Sophos XG instance to handle VPN traffic (IPS, strict firewall rules, packet inspection, etc). The Sophos firewalls can be centrally managed/monitored via Sophos Management Products (Sophos SUM (Sophos UTM Manager), and/or Sophos CFM (Sophos Central Firewall Manager)).
  • Why are we using an SSL VPN connection instead of IPSec or other type of VPN?
    • Microsoft Azure blocks some IP Protocol traffic within Virtual Networks. As quoted: “IP-in-IP encapsulated packets, and Generic Routing Encapsulation (GRE) packets are blocked within VNets” (per https://docs.microsoft.com/en-us/azure/virtual-network/virtual-networks-faq), which means that while you could configure an IPsec tunnel, none of the traffic would pass through the Virtual Networks. We utilize SSL VPNs to overcome this limitation as all traffic goes over the SSL connection.

Let’s address what components we will discuss in this post:

The information inside of this post can be used for any of the 4 components above and don’t necessarily have to be used in the same configuration. An example: This guide could be used by someone wanting to connect an on-premise XG and on-premise UTM unit together via SSL VPN (with no need or use for Azure). Another example: The section on routing tables can provide information for someone using a different network security product on Microsoft Azure. However, the ultimate goal of this article is to address all four of the components together for a complete end to end deployment.

Now let’s get to the configuration of each of the four components.

Deploy a Sophos XG instance/appliance to Microsoft Azure

In a previous post, I covered how to deploy a new Sophos XG firewall appliance/instance to Microsoft Azure, specifially allowing deployment to existing resource groups. The full URL (and instructions) can be found at https://www.stephenwagner.com/2018/05/05/deploy-sophos-xg-firewall-microsoft-azure-existing-resource-group/

Sophos XG to Sophos UTM SSL VPN Connection Configuration and Encryption Settings

We will configure the SSL VPN settings on both the Microsoft Azure Sophos XG appliance/instance, and the on-premise Sophos UTM appliance/instance. Afterwards, we will create a tunnel, configure it, enable it, and establish connectivity between the two Sophos firewall instances. During this process, we’ll be configring the SSL VPN settings on both appliance/instances, configuring the tunnel, configuring encryption settings, and establishing VPN communication.

Please note, with this configuration there are essentially 3 networks: the Azure network, the SSL transit network (this is the network in between the networks we are connecting that is part of the SSL VPN), and the on-premise network. When you configure your firewall rules (not in the scope of this document), you must factor this in and allow applicable traffic to/from the SSL network so that the packets can pass. This SSL transit network is specified in the “Show VPN Settings” on the XG unit under “SSL VPN”, and “IPv4 Lease Range”. This network must be different and not overlap any subnets you are using on both your Azure network, and on-premise network. In my case I chose something way off in an entirely different IP space (172.16.0.0), and I suggest you do as well.

Follow these steps to configure the SSL VPN settings on both Sophos XG and UTM appliances/instances.

  1. Log on to the Sophos XG appliance, select “VPN” under “Configure” on the left hand side, and then select the gear icon with “Show VPN Settings” on the top right. See example.

    Sophos XG Show VPN Settings

    Sophos XG Show VPN Settings

  2. Configure your “SSL VPN Settings” and “Cryptographic Settings” to be similar to the example below. Please modify to reflect your own environment. Cryptographic settings should match example below. Please note that the “IPv4 Lease Range” is not for your Azure or Internal LAN subnet, but actually the subnet used by the SSL VPN server. This value has to be an entirely new subnet dedicated for SSL VPN functions.

    Sophos XG SSL VPN Settings

    Sophos XG SSL VPN Settings

  3. Log on to the Sophos UTM appliance, select “Site-to-Site VPN”, then select “SSL”, then click on the “Advanced” tab.
  4. Configure your “Advanced” settings to reflect the following below.

    Sophos UTM SSL Site-to-Site VPN Advanced Settings

    Sophos UTM SSL Site-to-Site VPN Advanced Settings

You have now configured the general SSL VPN Advanced settings, we can now move on to configuring the tunnel itself.

To configure the SSL Site to Site VPN tunnel between the Sophos appliances, we’ll need to configure the Sophos XG (on Azure) to act as a server, and the Sophos UTM (on prem) which will act as the client. Side note: In my own testing, I found that the XG had to be the server in order to get them to connect.

To configure the SSL VPN tunnel Server on the Sophos XG:

  1. Log on to your Sophos XG interface, click on “VPN” under “Configure” on the left hand side, and then choose “SSL VPN (Site-to-Site)” from the top. Then click “Add” under the “Server” section. As shown below.

    Sophos XG SSL VPN (Site-to-Site) Settings

    Sophos XG SSL VPN (Site-to-Site) Settings

  2. Now give the VPN connection a name, enter a friendly description, and specify Local Networks (Azure Subnets), and Remote Networks (On-Prem Networks). And then click “Save” as shown below.

    Sophos XG Create new SSL VPN Server

    Sophos XG Create new SSL VPN Server

  3. Now we need to download the configuration so that we can load it on to your Sophos UTM so it know’s how to connect. While still in the “SSL VPN (Site-to-Site)” window, look for the column called “Manage”, and click the download icon (you can confirm it’s download via the mouse-over description). As shown below.

    Sophos XG SSL VPN Server Download Config

    Sophos XG SSL VPN Server Download Config

  4. Save this file to your computer as we’ll need it for configuring the Sophos UTM

To configure the SSL VPN tunnel Client on the Sophos UTM:

  1. Log on to your Sophos UTM web interface, click on “Site-to-Site VPN” on the left hand side, and then select “New SSL Connection”. As shown below in step 2.
  2. Set the Connection type to “Client”, give it a friendly name. Now click on the folder next to “Configuration File” to brows to the VPN config file (this is the file we downloaded above from the Sophos XG unit). In my case, I also selected the “Override peer hostname” as I wanted to over the hostname of the Sophos XG unit (to avoid problems I chose an IP address). This value sets the hostname of the server that the UTM is connecting to. We also uncheck the “Automatic firewall rules” as we don’t want any rules automatically created, we want to specify only what is needed.

    Sophos UTM Create New SSL VPN Connection

    Sophos UTM Create New SSL VPN Connection

  3. Hit Save, and you should be left with something like below.

You have now fully configured the SSL Site-to-Site VPN tunnel between your Sophos XG and Sophos UTM instances.

To confirm a functioning VPN tunnel on your Sophos XG unit, you should see something similar to below.

Sophos XG SSL VPN (Site-to-Site) Active VPN Status

Sophos XG SSL VPN (Site-to-Site) Active VPN Status

To confirm a functioning VPN tunnel on your Sophos UTM unit, you should see something simialar to below.

Sophos UTM Active VPN Status

Sophos UTM Active VPN Status

Please note that a bug with XG to UTM VPN, is that on the Sophos UTM reports the active subnets as “unknown” as shown above on both sides. This can be safely ignored.

You can start to test some basic communication, however you still need to create firewall rules. Please note that the Azure network will not be routable until you continue the steps below and configure proper routing.

Microsoft Azure VNet (Virtual Network) custom routing table

When you create a Virtual Network (VNet) in Microsoft Azure, Azure will handle the routing for you automatically. It will create routers and other “instances” to handle network connectivity as you provision new subnets, gateways, devices, and network paths. Since we are deploying our own router, we want to override these default routing tables that are automatically created.

When looking at our target configuration, our Sophos XG unit will have an internet facing static IP, and will be handling communication between our internal network (and hosts), the internet (outside world), and our internal on-premise network (LAN). Because of this, we have to make changes to our Azure enviroinment so that the default subnet network route becomes the Internal IP Address of the Sophos XG firewall. We need to configure routes for both our Azure subnets (if wanted), our corporate on-premise LAN, and our catch-all route for internet access (0.0.0.0/0).

Once we create our own routing table, we’ll need to assign it to specific subnets to make those specific subnets enforce the routes.

To create a custom Route Table:

  1. Log in to the Azure Portal, View “All Resources”, click on the “Add” button at the top to create a new resource, or simply click on “Create a resource” on the top left of the Azure Portal.
  2. Select Networking on the left side of the table, then select “Route Table”. See example below.

    Sophos XG Azure Add Resource Route Table

    Sophos XG Azure Add Resource Route Table

  3. Populate the fields, select the subscription, resource group, and the Location of where you’d like to place this. For “Resource Group”, select “Use existing”, and then specify the Resource Group you are attaching this to.

    Sophos XG Azure Create Route Table

    Sophos XG Azure Create Route Table

  4. Select “Create” to complete the creation of the route table.
  5. Now that we have a customer routing table, we want to create a route. With the “Route Table” object still open, open the “Routes” tab to open the page from the column on the left.
  6. Click on Add, and then create a route for the CIDR block that covers both your Azure subnets, and corporate on-premise LAN subnet. PLEASE NOTE: This CIDR block (Address prefix) should be large enough that it includes both your Azure subnets and your on-premise network. This will make this rule apply to all traffic destined for those networks. Under “Next Hop Type”, select “Virtual Appliance”, and then enter the IP address of your Sophos XG LAN Network interface. Then click save.

    Sophos XG Azure Route Table LAN Route

    Sophos XG Azure Route Table LAN Route

  7. Click on Add, and then create a catch all route for the internet/WAN with an address prefix of 0.0.0.0/0. Under “Next Hop Type”, select “Virtual Appliance”, and then enter the IP address of your Sophos XG LAN Network interface. Then click save.

    Sophos XG Azure Route Table Internet Route

    Sophos XG Azure Route Table Internet Route

  8. The Route’s section should look similar to this.

    Sophos XG Azure Route Table Route List

    Sophos XG Azure Route Table Route List

  9. Now we need to assign the route table to the chosen subnets. This will apply the routes we created above to specific subnets on our Azure Virtual Network (VNet). With the “Route Table” object still open, open the “Subnets” page from the column on the left.
  10. Click on “Associate” to add this to an existing subnet. And then associate it to your Azure Virtual Network subnet where the XG and your VMs reside.

    Sophos XG Azure Route Table Associate Subnet

    Sophos XG Azure Route Table Associate Subnet

  11. Now completed, the “Overview” tab should look similar to this.

    Sophos XG Azure Route Table Overview

    Sophos XG Azure Route Table Overview

You’ve successful configured a custom routing table for your Microsoft Azure subnet which will route packets destined for other subnets (including internet/WAN) to your Sophos XG for further routing.

Microsoft Azure enable IP Forwarding on Virtual Network Interface

In order for a VM (Virtual Machine) to have the ability to forward and route packets, we need to enable “IP Forwarding” on both the Internal and External NIC of the Sophos XG appliance running on Azure.

To enable this:

  1. Log in to the Azure Portal, view “All Resources” and select one of the “Network interface” objects for your Sophos XG appliance/instance.
  2. Click on “IP configurations” under the “SETTINGS” group.
  3. Look for “IP forwarding” under “IP forwarding settings”. Set this toggle to “Enabled” as per below.

    Enable IP Forwarding on Microsoft Azure Network Interface

    Enable IP Forwarding on Microsoft Azure Network Interface

  4. Click Save
  5. Repeat for the other Sophos Network interface (both External and Internal need this enabled)

IP Forwarding has now been enabled. The Sophos XG appliance can now successfully route packets in your Microsoft Azure Virtual Network (VNet).

Conclusion

At this point you’ll have everything configured. You’ll have a SSL VPN between your Azure hosted Sophos XG instance and your on-premise Sophos UTM, as well as connectvity between both of the networks. You will now need to configure all your firewall rules to only permit the traffic you want to traverse from internal-azure to internal-onprem as well as external WAN traffic (this is beyond the scope of this document). You need to take care in making sure you only permit traffic that should be going over these network links. Now that both networks are connected, it provides another means to connect and communicate with the other networks which increases your security risks. You’re not only securing against one internet connection on one LAN, but 2 internet connections across 2 networks.

In my scenario by configuring this I was able to decommission the Microsoft Azure VPN Gateway (minimizing costs), and have my own security appliance/instance handle the communication between both networks and also protect both networks with all the fancy features that the Sophos XG and UTM line offer.

Leave a comment with feedback!

Dec 152017
 

The Challenge

Finding a cost-effective SIP trunk provider in Canada can be one of the biggest challenges that a business may have when trying to adopt VoIP technology. This is also a common problem for VoIP PBX re-sellers, as it’s hard to find a good provider to refer.

Back in 2007, just a year in to running my own company, my telecommunication and voice requirements massively grew. I needed a phone system to handle multiple extensions, call forwarding, conference rooms, follow-me services, rings groups, and needed the ability for staff and contractors to have their phones (and extensions) in remote offices or home offices. Also, I was travelling quite frequently so I needed to be able to have an extension running on my smartphone (so it would appear as if I was at the office, and to save on international roaming and long distance costs).

Implementing a VoIP PBX phone system handled all of this, and was very easy to implement however finding an SIP trunk provider was not. Originally I was using FXO/FXS adapters to pipe analog lines in to my PBX, however I wasn’t happy with the quality or the complexity of a solution. I wanted a true 100% digital, and 100% Canadian hosted solution.

The Solution (The Review)

After spending months researching providers, I came across a company called Iristel. There were numerous great reviews on the internet, and most importantly they had a following of Trixbox (Asterisk) users, so I could verify they would work with my PBX. They were a Canadian company (important to me), who provided SIP trunks at a great cost. I signed up for service, and tech support was actually amazing at providing assistance for configuring the SIP trunks with my Asterisk PBX, their sales staff was pretty awesome as well!

Here’s where the review gets boring (which is a good thing), I’ve been using them for around 10 years now, and everything has always just worked! I think in 10 years, I may have experience a single 1-2 hours of downtime, and this was due to a compatibility issue with Asterisk and their SIP gateways caused by an update (SIP registration bug). In this one-off case, tech support was immediately available and made configuration changes to resolve this issue. Outstanding service to say the least!

Over the years, I’ve also re-configured and deployed new PBXs. I’m now using FreePBX, and Iristel is still working great! AND YES, Iristel supports T38 faxing!

I would definitely recommend Iristel as a your VoIP SIP provider for your business digital telephony needs!

 

Feel free to reach out (comment) if you have any questions about my review, or the quality of the services.

Nov 062017
 

Something that has bothered me for a very long time has been the fact that mobile devices (using Microsoft Exchange ActiveSync), automatically send read receipts if the sender has requested it without prompting the user. This means that if someone sends you an e-mail, requests and read receipt, and you open it on your mobile device; it will send a read receipt without prompting you or giving you a choice in the matter.

This is bad for a number of reasons such as spam (this is a big one, where they try to validate e-mail addresses), legal reasons, you don’t have the time to respond and don’t want a read receipt sent yet, or you simply don’t send read receipts…

Now, with Microsoft Exchange 2016 you can disable this so that mobile devices don’t automatically send these read receipts out. It’s a simple procedure using Outlook on the web (previously known as Outlook Web Access, a.k.a OWA).

To disable automatic read-receipts:

  1. Log on to your OWA (Outlook on the web) server.
  2. Click on settings (the gear) on the top rightOutlook on the Web (OWA) Settings
  3. Expand the “General” settings menu, and select “Mobile Devices” (as shown below)
    Outlook on the Web (OWA) Settings Pane
  4. Check the checkbox for “Don’t send read receipts for messages read on devices that use Exchange ActiveSync”.
    Don't send read receipts for messages read on devices that use Exchange ActiveSync

You’re done!

Nov 062017
 

After doing a migration from Microsoft Exchange 2013 to Exchange 2016 I noticed that my Offline Address Book (OAB) wasn’t being made available to Outlook clients.

When trying to perform a manual download (Send and Receive -> Download Address Book), it wasn’t in the list. Also when using the “Test EMail AutoConfiguration..” (by holding CTRL and right click on Outlook System Tray icon) to examine the AutoDiscover information, there was no OAB URL (OABUrl in XML) being sent to the clients.

I spent 3 hours trying to find out why this was happening (I assumed it was configuration and/or IIS authentication related). All my virtual directories and URLs were fine, and the OAB was being generated fine without any issues. It simply wasn’t being passed to Outlook clients. I couldn’t find any references of this occurring to other users.

I finally discovered that the “WebDistributionEnabled” configuration flag was marked to False, when it needs to be marked as True. This flag when set to true, allows it to be distributed (Note/Fun Fact: There’s a separate and different flag for older Exchange versions where the OAB is inside of the Public Folder Store). There’s also a different flag “GlobalWebDistributionEnabled”, which is recommended to be enabled as well on Exchange 2016. When setting this second flag to True, it also sets the first one above to True as well.

To fix it we’ll use Exchange PowerShell:

Let’s find the name of your Offline Address Book by running the command below:

Get-OfflineAddressBook

Exchange Offline Address Book Get-OfflineAddressBook

Now let’s set the “GlobalWebDistributionEnabled” flag to True using this next command:

Set-OfflineAddressBook -Identity “Default Offline Address Book (Ex2016)” -GlobalWebDistributionEnabled $true

Set Offline Address Book Microsoft Exchange 2016 Default Set-OfflineAddressBook

And finally let’s confirm to make sure the changes take effect and look for the values of “GlobalWebDistributionEnabled” and “WebDistributionEnabled” using the command:

Get-OfflineAddressBook | fl

Get-OfflineAddressBook WebDistributionEnabled GlobalDistributionEnabled

 

After making the above changes I recommend issuing an “iisreset” or restarting your Exchange Server. There will also be a delay where you’ll need to wait for your Outlook clients to refresh their autodiscover configuration. You can run the “Test Email AutoConfiguration…” to see if the OAB is now being passed to your clients.

Oct 192017
 

In the past few days, I’ve noticed that some Sophos UTM firewalls I manage for clients haven’t been sending their daily reports (or other notification e-mails). When I first noticed this, checking my own SMTP proxy, I noticed that the e-mails were being sent from the firewalls, but were being dropped due to an SPF check failure.

Originally I thought this may have just been an overnight glitch with the DNS providers, however I later noticed that it’s stopped all e-mails coming from all the UTMs.

Further investigation, I realized that by default, the Sophos UTMs send their firewall notifications (and configuration backups) from the domain “fw-notify.net”, specifically, the e-mail address “do-not-reply@fw-notify.net”. That’s when I had a brainfart and realized the e-mails weren’t being sent from my clients owned domains, but this fw-notify.net domain.

It appears that recently some SPF records have been created for the domain “fw-notify.net”, which is what is causing this issue. Also, I’m not quite sure if the domain underwent ownership change, or it his was overlooked by someone at Sophos.

I’m assuming numerous other longtime UTM users will be experiencing this as well.

To fix this, just log in to the problem UTMs, and change the notification Sender address as shown below to a domain you own. I changed mine to fw-notify@mydomainname.com (which has valid SPF since it’s my domains relay).

Oct 182017
 

Well, it’s October 18th 2017 and the Fall Creators update (Feature update to Windows 10, version 1709) is now available for download. In my particular environment, I use WSUS to deploy and manage updates.

Update: It’s now May 2018, and this article also applies to Windows 10 April 2018 update version 1803 as well!

Update: It’s now October 2018, and this article also applies to Windows 10 October 2018 update version 1809 as well!

I went ahead earlier today and approved the updates for deployment, however I noticed an issue on multiple Windows 10 machines, where the Windows Update client would get stuck on Downloading updates 0% status.

I checked a bunch of things, but noticed that it simply couldn’t download the updates from my WSUS server. Further investigation found that the feature updates are packaged in .esd files and IIS may not be able to serve these properly without a minor modification. I remember applying this fix in the past, however I’m assuming it was removed by a prior update on my Windows Server 2012 R2 server.

If you are experiencing this issue, here’s the fix:

  1. On your server running WSUS and IIS, open up the IIS manager.
  2. Expand Sites, and select “WSUS Administration”
  3. On the right side, under IIS, select “MIME Types”
  4. Make sure there is not a MIME type for .esd, if there is, you’re having a different issue, if not, continue with the instructions.
  5. Click on “Add” on the right Actions pane.
  6. File name extension will be “.esd” (without quotations), and MIME type will be “application/octet-stream” (without quotations).
  7. Reset IIS or restart WSUS/IIS server

You’ll notice the clients will now update without a problem! Happy Updating!

Nov 102016
 

I recently got my hands on a D-Link DCS-5222L IP Camera and thought it would be pretty cool to get it setup to do YouTube Live streaming. To configure the stream I would have to find a way to convert and encode the RTSP stream from the camera to a YouTube Live compatible RTMP stream.

I figured I would see if I could use VLC or FFMPEG to convert the stream. I had no luck with VLC however I found out ffmpeg should do what I needed to do. I couldn’t easily find the proper usage command and flags, however eventually after viewing multiple sites, mixing, matching, and testing, I found this command worked:

ffmpeg -rtsp_transport tcp -i rtsp://IP.CAM.ADD.RESS/live1.sdp -framerate 30 -video_size 1280×720 -vcodec libx264 -preset veryfast -maxrate 1984k -bufsize 3968k -vf “format=yuv420p” -g 60 -c:a aac -b:a 128k -ar 44100 -f flv rtmp://YOUTUBELIVE/DIR/StreamKey

Happy streaming! And if anyone can refine, or recommend better command usage, please post in the comments!