Quickie: Importing Certificate Into Juniper Devices

Working in a Juniper SRX (or other model), you might have a need to secure the web interface with a certificate through the CLI. I had this need and ran into a problem where Junos wouldn’t recognize the input I gave in the CLI for the certificate (it was an issue with line breaks). The web management service wasn’t starting and I was receiving errors like the following in the httpd.log file:

httpd: Error: OpenSSL: Can't open certificate file: /var/etc/ssl/https.pem
httpd: Error: OpenSSL: Can't configure certificates

Searching online, there isn’t much that talks about this process, so this is an attempt to rectify that. The following is a quick breakdown of how to import a certificate into a Juniper SRX via the CLI. The process should be applicable for all Juniper devices (EX, MX, etc.), but I’ve only tested it on SRXs in 15.x+.

Generate Certificate

First off, generate a certificate. I’m not going into the details of how to generate a certificate because that’s outside the scope of this post, and your certificate process will vary.

For this process, I generate certificates outside the Juniper device with some scripts, so no need to create a CSR on the Juniper device and so forth. Typically I use a 2048 to 4096-bit key, and I like to create SAN/UCC certs for these device types so that I can include the hostname, FQDN, and IP address.

One important item here to note: your certificate format needs to be in base64/PEM format. In other words, it should be a file that looks something like this:

Example text output of base64/pem certificate.

And your unencrypted private key like this:

Example text output of RSA private key

Combine Private Key and Certificate Into Single Line

Next, I open up VS Code and concatenate the private key and certificate into one file:

Example of RSA private key and certificate as one file

Now we’re going to replace all the line breaks with line breaks that Junos recognizes. Using below for reference, hit Ctrl+F (Find) or Ctrl+H (Replace) to get the find and replace box and click the drop-down arrow. Next switch to using regex (red arrow), then type ‘\n’ in the search field (pink arrow), type ‘\\n’ in the replace field (green arrow), and then click ‘Replace All’ button (blue arrow).

Example of using find and replace in VS Code

The end result should look something like this:

Example of RSA private key and certificate as a single line

Configure Certificate in Junos

To import configure the certificate in Junos, just copy the single line you created above then in configuration mode, enter the set command like below (with your single-line in-between the quotes):

set security certificates local <Junos Name for Cert> "<Transformed Private Key and Certificate>"

Example:

set security certificates local EXAMPLE-CERT-NAME "-----BEGIN RSA PRIVATE KEY-----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\nN1jEnRqpAwEdw7S+8l0yVyaNkm66eRI80p+w3AxNbS9hJ/7UlV3lGA==\n-----END RSA PRIVATE KEY-----\n-----BEGIN CERTIFICATE-----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\n+tZ9KynmrbJpTSi0+BM=\n-----END CERTIFICATE-----"

Commit the config and you’re set.

Optional: Set the Certificate in Web Management

If you haven’t set a certificate yet for the web-management service, the command below will configure it with the certificate name you used:

set system services web-management local-certificate EXAMPLE-CERT-NAME

Optional: Restart Web Management

As a general practice from managing Linux boxes, I like to restart the web management service. In operational mode, run the following to restart the web-management service:

restart web-management

That’s it! You should be set.

Monitor or View Log Files

If you want, you can look at the httpd.log file to watch the process:

monitor start httpd.log #monitors log file

or

show log httpd.log

 

Palo Alto GlobalProtect Issue: Split Tunnel VPN with Skype for Business

There was a weird issue when I first joined my current job: I was told was that because of the way Palo Alto GlobalProtect (GP) and Microsoft Skype for Business (SfB) works (or maybe was configured?), I needed to log-in to SfB first, then connect to the GP VPN. The rationale was that SfB wouldn’t connect, or it would take a long time to connect, AND THEN even after a period of time, SfB would start behaving weird and it’s Exchange connectivity would drop, so SfB wouldn’t get voicemails, missed calls, etc. Just all out weirdness going on. It’s 2020, so maybe some of this true to form for the year, but probably not.

Palo Alto GlobalProtect Skype for Business

Click here if you want to skip the context and go to the solution.

Uh…Skype for Business?

Full stop. I’m sure you’re asking yourself right now, “Why not just migrate to Microsoft Teams? Get rid of that whole on-premises stuff.”

Let me answer that in a meme:

Sean Beam Boromir Meme: One does not simply migrate from Skype for Business to Teams

Skype for Business is one of the integrative technologies that spans lots of technology stacks that isn’t exactly easy to just jump ship from, and Teams as a VoIP replacement is arguably not there yet.

Also, have you seen the UI comparisons? Going from a sleek floating window for calling, IM, and conferencing with SfB to the giant-lets-pack-lots-of-services-into-one-large-window that is Teams is kind of a hard sell on the user training side of things. Maybe I’m biased. Maybe, but I digress.

The Challenge

Ok, back to the GlobalProtect and Skype for Business issues.

I was admittedly puzzled that the solution — to instruct users to sign-in to SfB before they sign-in to the VPN — was the best solution; it doesn’t seem right from a user experience perspective, and then when you toss-in the sudden weird issues with Exchange connectivity, none of this seemed right, and I doubt that’s the ideal experience. So I brought this up and the team basically said, “we just haven’t had time to troubleshoot it, but if you want to figure it out, go for it.”

You know what that sounds like? An adventure. An itch to itch. Something to solve. A challenge! There could be only one response:

Challenge Accepted Meme

Why Split Tunnel Skype for Business?

Something you might be asking is “Why configure split tunnel in the first place? Isn’t split tunneling a headache to manage?”

Split tunneling can definitely be a PITA, but like a million IT questions out there, the answer ultimately to this is, “it depends.” From my experience, split tunneling becomes difficult when you have a lot of split tunneling to manage, but if you have one or two services, it’s not that bad.

For Skype for Business, it’s one of those technologies that is sensitive to jitter, latency, and packet loss. Why? It’s because it’s voice traffic, and just like voice traffic on the inside of the network, where there’s jitter, latency, and/or packet loss, users on opposite ends of calls/conferences will experience this as delayed audio or parts of the conversation will just break up and it leads to an overall poor experience.

When you configure split tunneling, particularly for technologies like SfB, you avoid the dual encryption scenarios and you allow the technology to use its own optimized methods for connecting voice and application traffic by letting the software connect to services over the internet directly versus through a tunnel.

Baseline

That said, what’s the baseline here? How is GlobalProtect configured with split tunneling and what issues are there?

For GlobalProtect, the split tunnel configuration was configured pretty much like this documentation from Palo Alto (using just the application split tunnel, nothing else). It looked like this:

GlobalProtect Split Tunnel Domain and Application Tab Showing Excluded lync.exe

Here are the issues that were encountered in this setup:

  1. Connectivity issues if connecting SfB after GP VPN is connected
  2. Exchange connectivity in the SfB client drops after a duration of time, even if connection is established before VPN connection
  3. Call transfers working inconsistently
  4. Application sharing working inconsistently
  5. Conference meetings working inconsistently

Issues 3-5 really came later because they were hard to pinpoint due to their inconsistency, but issues 1 and 2 brought some fast wins.

Let’s get to some solutions.

Solutions

Solution for 1 and 2: DNS. It’s always dns.

It’s kind of a joke, but DNS really does cause a lot of problems, and in a split tunnel configuration when you’ve split-tunnel the traffic by application, the application is still going to resolve addresses by the servers you specify in the GlobalProtect configuration. So if you haven’t changed DNS records, the application will split tunnel, but it will still try to connect to internal resources because that’s the records it has.

I don’t have a PCAP screenshot for this, but if you pull up Wireshark and look at the PCAPs for your network interface (non-GP interface), you’ll see attempts to get to SfB internal IP addresses that aren’t (typically) on your network, and thus services fail.

The solution is simple: for your VPN clients, serve the external IP addresses for A records being queried. I solved this by setting up dedicated DNS servers for VPN clients, then just creating the zones and root records for each FQDN. I did this for all the Skype for Business external IPs (edge and reverse proxy) and the external Exchange records.

After doing this, problems 1 and 2 went away because hostnames were being resolved correctly.

Solutions for 3 through 5: Firewall rules and IP Split Tunneling

Problems 3 through 5 were frustrating like no other because I couldn’t really narrow the problems down exactly. Some people had no problems with call transfers, application sharing, or conferencing, but then sometimes they would. So the thing to do is dig into the logs, and when I did I encountered a lot of this:

ms-diagnostics: 23;source="mediationServer.contoso.com";reason="Call failed to establish due to a media connectivity failure when one endpoint is internal and the other is remote"

Or

ms-diagnostics: 24;source="mediationServer.contoso.com";reason="Call failed to establish due to a media connectivity failure when both endpoints are remote"

Or even better:

ms-client-diagnostics: 52049; reason="Leaving app sharing because re-invite failed";UserType="Callee";MediaType="applicationsharing-video"

These all pointed to firewall issues, and even the ICEWARN messages noted something wrong with STUN, TURN, NAT, etc.

So I did some digging and found that firewall rules needed to be in-place to prevent VPN clients and internal SfB servers from communicating with one another. So I added some PAN policies, and things got better, but not perfect. Also, I added the external SfB IP addresses to the split tunnel in Network > GlobalProtect > Gateway > Agent > Client Settings > Client-Config > Split Tunnel > Exclude (which basically just adds static routes in the Windows routing table to send traffic for those IPs out the non-tunneled interface). Still the occasional error creeping up, and I could even witness it, but still can’t quite nail the problem.

Finally, I had a thought: why not get rid of the application process split tunnel? I mean, if I have DNS addreses configured, and IP split tunneling working, why is the application process split tunnel needed? Removed that from the setting and bam — all the problems went away. Like magic.

Shia Labeouf Magic

Here’s what the final outcome should look like for a GlobalProtect-Skype for Business-Exchange environment for split tunnel.

Palo Alto GlobalProtect Skype For Business Split Tunnel

Of course, I fully admit this is really more of a legacy design with everything on-premises, but you could just as easily send the Exchange traffic to Office 365 in the split tunnel.

Thoughts on GlobalProtect Application Process Split Tunnel

While I had configured the traditional methods of doing split tunnel configurations (IP split tunnel and DNS servers), I’m still a little puzzled to the fact that the Palo Alto GlobalProtect application process split tunnel seemed to cause issues. My guess is that something in the way the Skype for Business client is designed prevents the process from being completely split tunneled, and I think this has to do with the way Skype for Business operates with Windows.

If you get really bored on a Friday night and have nothing better to do in life, check out some of these deep dives on candidate path selection and other stuff related to media flow. What you’ll see in the SfB client log files is something like this:

Skype for Business candidate selection
Credit

Basically, SfB gets a selection of candidates that it uses from the interfaces on the computer. In a GP split tunnel set up (with or without application process split tunnel configured), you’ll see ALL IP addresses (including the tunnel address) listed as candidates, and my suspicion is that Skype for Business still tries to use a tunnel interface, and sometimes it gets around the Palo Alto GlobalProtect application exclusion, and then that causes calls, application sharing, and even conferences to fail. I can’t show my own logs seeing this for security reasons, so you’ll have to trust me on that one.

Solution (tl;dr)

Here’s the quick solution for GlobalProtect and Skype for Business Split Tunnel

  1. Create separate DNS servers for VPN clients and create the specific Skype for Business DNS records needed, and configure them for external IP addresses so that Skype for Business resolves external addresses and configures itself appropriately.
  2. Create firewall rules that block traffic to/from the VPN network to internal Skype for Business and Exchange IP addresses. We want the SfB client to determine it can’t go inside for traffic.
  3. In Panorama or PANOS, under Network > GlobalProtect > Gateway > Agent > Client Settings > Client-Config > Split Tunnel > Exclude, configure all external SfB addresses so that the GP client doesn’t send traffic for those IPs through the tunnel. Alternatively, under Network > GlobalProtect > Gateway > Agent > Client Settings > Client-Config > Split Tunnel > Domain and Application > Exclude Domain, you could add the SfB external FQDNs (that said, IIRC, the stuff under ‘Domain and Application’ requires the GlobalProtect license…technically).

Links, Further Reading, Credit

pyribbon: Python Module for Sonus/Ribbon SBC REST API

Part of my recent stumbling into supporting VoIP systems again is supporting and maintaining Ribbon session border controllers (SBCs). SBCs are pretty much gateways/routers and even firewalls for VoIP traffic, which not only routes/limits traffic between disparate voice systems (like ISDN lines to SIP trunks), but can also manipulate the traffic such as adjusting the phone number format, media codec, changing SIP header information, yada yada — you get the point.

Diagram showing Ribbon SBC connecting to different systems

Pretty much all SBCs are configured via extensive web interfaces with lots of deep options, so if you have to manage these at scale, it can get a little time consuming — which is what my problem was. I have many SBCs scattered across our state, and I generally loathe having to make mass changes via any GUI, so does Ribbon have some method of configuring SBCs at scale? Yes, through its Ribbon API.

However, I’m not going to sit down and use Postman to configure these (well, maybe initially to test), so I need a scripting framework. I could use PowerShell or curl with bash scripting to do this, but most of my work in networking is done via Python, and thus because I couldn’t find any Python module built for this already (and it seemed like fun to create), I made this simple Python module and it’s on Github.

pyribbon: Python Module for Sonus/Ribbon SBC REST API

I wrote this with a VoIP engineer in-mind, and the basic idea is you import the module in a Python script, then interact with source of data to make changes or perform actions. For example, I’ve used it to create a ton of phone number changes with the routing and transformation tables, and I’ve used it to perform configuration backups across all systems.

To do most of this though, you need to get familiar with API and how object resources are designed. Personally I started with Postman and got a sense for how the API works, then I built the class to handle the API. Initially I started small, but then realized it was rather simple to add additional methods to the pyribbon class to perform different tasks. One could easily build additional methods such as reboot, backup, etc., but I just didn’t see the need for that — yet.

One potential cool use is to perhaps use the module to query for call statistics and send that to a database, then maybe graph it out with Grafana; or, if your NMS allows for script pollers, perhaps use that versus digging through SNMP OIDs.

Final thoughts: I know this is probably high on the esoteric use-cases. I mean, how many VoIP engineers are there in the world, then narrow that down to Sonus/Ribbon VoIP engineers, then dwindle that down to those that interact with the API, and then dwindle that down even more that do it via Python. Pretty small, but if you like Python for this kind of work, this should help.

Also, I thought about putting this in PyPi, but I can’t imagine this getting much use or further development on my end (it does what I need it to do well), and thus I’m shying away from that.

Let me know if you find this useful or have questions.

Skype for Business: Cleanly Shutting Down Server (Invoke-CSComputerFailover and More)

It’s been over three years since I managed and deployed a Skype for Business/Lync system, and at my new job I was hired on as a be a network engineer, but I noted in a past life I received a MCSE in Skype for Business, so I could definitely be the backup for the primary SME (subject matter expert) in SfB. However, in a strange twist, the primary SME left — and you know what, there’s just not a lot of Skype for Business/Lync engineers out there, especially in a small labor market, so I stepped up to help the organization because I was the most qualified by a long-shot.

So I’m back doing some Skype for Business again.

Captain America Here We Go Again

I actually have always liked voice routing, so it’s fun to be doing some of this stuff again (although SfB is a pretty intense, integrative technology, so it’s not all Pop-Tarts and unicorns).

However, I was trying to get reacquainted with some commands for cleanly shutting down a Skype For Business server, and I just didn’t find a lot of good information out there, so I thought I might write something up “real quick”. This is somewhat basic info for SfB enterprise deployments, but it might be helpful.

Enough of the pretext, let’s get to the first command…

Get-CSWindowsService

I’m starting with this command because it’s the most basic command you should already know, but plays a role for later in this post. Typically you’ll use the command to see how many connections are being used by a service, if a service is running, etc.

The command is straightforward: Get all or one of the SfB (or Communication Server, which is where the acronym CS comes from) Windows Services on the machine.

Stop-CSWindowsService

The command `Stop-CSWindowsService` is the most basic command you’ll use to stop all or one of the services on a SfB server. The command will execute stopping of services in the proper order of stopping SfB services, including any dependent services.

Typically you’ll be using this command on a ‘Standard’ deployment SfB server, or any non-front end server in an ‘Enterprise’ deployment such as mediation/edge servers (more info: standard vs enterprise deployment). However, there are probably rare situations in which you’ll stop just one service, so you’ll likely be stopping all of them.

If you’re doing this outside a maintenance window for some reason, I prefer to do the following: Stop-CSWindowsService -Graceful. The -Graceful is important here, because what it does is it puts the services into a paused state, preventing any new connections from happening and waiting on existing connections to disconnect. On mediation servers, whenever I’ve need to stop a server in a mediation pool, this is my preferred method so that I wait for the calls to end. However, it won’t stop until the call is done, so you might be waiting awhile.

Invoke-CSComputerFailover

For whatever reason, this command scared me at first, largely because of my ignorance of what it does. The official documentation on the command I don’t think does it justice, so here’s my attempt at it.

The command `Invoke-CSComputerFailover` will basically perform a Stop-CSWindowsService -Graceful operation, but it acts slightly different. The differences:

  1. It’s used on front end servers in an enterprise deployment (or at least I’ve never seen it documented or used on other SfB server pools). The command causes the front end server to be in a ‘failover’ state, making it unavailable to the rest of the front end pool.
  2. The command migrates data, routing groups, and more to the other front end servers.
  3. The command has a wait time of 1 hour per service, after which if the connections haven’t disconnected, it will force a disconnect. This default can be changed with the `-WaitTime` parameter.
  4. This command will make the server unavailable in the front end pool. After a reboot, or if for some reason you run Start-CSWindowsService, the server won’t be available until you run Invoke-CSComputerFailBack.

After working with it and using it several times, it’s not as scary as I thought. Just run it on one machine at a time lest you have some Windows Fabric issue due to quorum loss (or something to that effect).

Invoke-CSComputerFailover Hanging or Taking Awhile

Sometimes when you’re failing over a front end server, you get stuck waiting for some services to stop like this:

Status screen waiting for Invoke-CSComputerFailover to Progress

If you look at `Get-CSWindowsService`, you might actually find something like this:

Get-CSWindowsService Seeing Services With Hanging Connections

If you note the red and blue arrows, the services are left open, likely from a conference that has ended already, but is being left open for whatever reason. To speed up Invoke-CSComputerFailover, just open a separate elevated terminal and stop the services like this:

Stopping the stalled services with Stop-CSWindowsService in separate window

After which, `Invoke-CSComputerFailover` will continue on as expected.

Invoke-CSComputerFailover progressing

I originally tried out the idea on my own, but the following blog entry also helped me and explains it from a different perspective.