Networking

After how woefully lacking in detail for the novice in OS 10 switches the Dell documentation is below is a little snippet that can be used to configure your switches with what appears to be enough permission for PRTG (or a similar SNMP monitoring system) to keep an eye on them.

After entering configuration mode a readonly view with a base OID is set (I’d be grateful for some feedback on this!), then a group (prtg) is created to contain the user and defines readonly permissions, finally a user (prtguser) is created, assigned to the group (prtg) and the relevant password and privacy encryption strings set.

configure
snmp-server view readonly 1.3.6.1.2.1 included
snmp-server group prtg 3 priv read readonly
snmp-server user prtguser prtg 3 auth sha LONGANDSTRONGAUTH priv aes LoNGANDSTRONGPRIV
exit
write memory

Logs from the FreeIPA server can be used with the Syslog receiver function of a PAN NGFW to send username to IP address mappings into User-ID and in turn be used to create policies based on the users identity. To extract the data from the logs you will need the parser shown below.

I could only find a log that matched up with a login (nothing for a logout) and it’s worth a mention that you may need to exclude some servers (like mail servers and file servers) from User-ID as you will see multiple logins from multiple users over a very short period of time.

In recently deploying the Captive Portal feature of a Palo Alto Networks Next Generation Firewall (NGFW) in testing we were finding Apple Macs take 120+ seconds to load the sign-in page. First thoughts jumped to the Apple Captive Network Assistance (CNA) feature not functioning correctly however this appeared to be a dead end. Some time and a few packet captures later showed that the Mac wasn’t even trying to reach out to the Captive Portal in a timely manner, after much head scratching the customer I was working with suggested that their Sophos Endpoint agent (Intercept X) might be the cause of this problem.

Disabling the agent didn’t seem to resolve the issue however uninstalling it did – the Captive Portal page appeared nearly instantly. In reviewing the packet captures again it was clear the Sophos agent was trying to reach out to a reputation service which was being blocked by the authentication profile on the firewall, it just took a really long time for the agent to stop trying and allow access to the Captive Portal.

To work around this issue the domains listed in the link below were added to an authentication bypass policy on the NGFW, with this in place the Captive Portal loaded promptly. If anything it makes sense to allow unauthenticated access to such services (including Windows Update and the likes) to ensure a client has the ability to update itself regardless of authentication status.

https://doc.sophos.com/central/Customer/help/en-us/PeopleAndDevices/ProtectDevices/DomainsPorts/index.html

After a few years on hold it’s great to be back at CITC this time in the British Motor Museum. The video presentation covers a short (if speedy) introduction to Node-RED and it’s ability to integrate systems through their APIs.

Demo 2 is of note and shows how a user visiting a malicious website can have their internet access revoked until a helpdesk agent has a chance to clean-up their machine and then grant access again without even having to login to the firewall controlling that access.

A little treat that I hope will help someone at some point, for those with Palo Alto Networks Next Generation Firewalls (NGFW) and Aruba Instant Wi-Fi you can forward syslog messages from the controller to the NGFW and parse them with the profile below to map users to IP addresses.

There is plenty of information on syslog to User-ID at this link for those just getting started: https://docs.paloaltonetworks.com/pan-os/10-1/pan-os-admin/monitoring/use-syslog-for-monitoring/configure-syslog-monitoring.html.

The text strings you will need are:

  • User authenticated
  • username-([a-zA-Z0-9\_\.\@]+)
  • IP-([A-F0-9a-f:.]+)

Having recently moved home I have become a part of the privileged few (hopefully not for long) in the UK to have fibre-to-the-home (FTTH sometimes known as fibre-to-the-premises or FTTP). Not wanting to use the EE provided all in one modem/firewall/router/switch/access point I have a setup that uses the pre-installed BT Openreach Nokia modem (ONT) a pfSense firewall/router along with a Ubiquiti switch and (eventual) pair of Ruckus wireless access points.

From the BT Openreach modem a copper cable (probably Cat6) connects to the WAN interface on my pfSense firewall. EE provide some guides (see links below) that provide some handy pointers but don’t answer all the questions.

EE guide 1 – How do I use my own router for home broadband?
EE guide 2 – What are my home broadband internet settings?

Working out your username (and password)

As described in the guides your username will be in the format PRODUCTIONHQNUN<NUMBERS>@fs after a little bit of poking around the username is the same as the EE account number which can be found at  https://mybroadbandaccount.ee.co.uk/b2cselfcare/b2c/myaccount > select your active account > it’s the number in the round brackets.

For example the username based on the (redacted) account number as shown below could be PRODUCTIONHQNUN48123456@fs.

Your password will have been set when you first signed up for Broadband/your EE account (if you have changed your EE account password since first setting it it’ll likely still be the first password set). If you can’t remember this or don’t know it you will probably have to call 150 to see if it can be recovered (or changed).

Plugging it into pfSense

With this information in hand hop into your WAN interface on pfSense and configure as shown below. Firewall/NAT configuration is out of the scope of this guide but the defaults configured in pfSense will normally work well as is.

Ruckus Cloudpath is quickly turning into one of my favourite add-ons for a wireless network in a residential/University setting. It’s doing this by letting users bring all manner of ‘smart’ devices into an ‘enterprise grade’ network and connect them securely with a personal WPA2 pre shared key.

Even better Cloudpath has loads of options for customizing the onboarding portal – the little tutorial below shows how to change the colour of the font in the footer of the page with a custom CSS file.

ResultIt’s a bit of an odd situation but sometimes you might want to take information from a cloud service in this case Cortex XDR from Palo Alto Networks and drag it into an on premise logging service. This guide will have a look at how to get this log data in as well as parse it such that you can break out the individual fields in the log entry.

In looking at the documentation it appears that the logs are in the Comment Event Format (CEF) but are then wrapped up in syslog for transmission. Although Graylog can absorb CEF directly this additional layer of syslog means we have to take in the syslog and then send the event messages through a processing pipeline in Graylog to extract the CEF data.

So onto the guide – which assume you are familiar with the operation of the Cortex XDR management console and Graylog (shown version is 3.3), for simplicity the code snippet you’ll need is also shown below from GitHub.

Code snippet from the screenshot sequence:

A handy trick I learnt recently from this video (ICX Serial Console Server with Raspberry Pi by Terry Henry) which I’ve condensed into this screenshot guide. In short the ‘screen’ command in Linux can be used to turn any device into a serial console server – very handy if you need ‘out of band’ access to the management console of devices. This can be very handy for Firewalls/Routers/Network Switches where a misconfiguration (and forgetting to set a rollback) can lead to the administrators network connection to the device being cut off.

This guide assumes you have some experience of using the Raspberry Pi (although this will work on many other types of hardware) and Linux.

If you are looking to build out Zone Protection Profiles on your Palo Alto Networks Next Generation Firewall then it can be handy to know just what your connections per second metrics look over time for each zone. Quite lucky Palo Alto Networks have a little (although not entirely descript) guide on where you can get this data – https://docs.paloaltonetworks.com/pan-os/9-1/pan-os-admin/zone-protection-and-dos-protection/zone-defense/take-baseline-cps-measurements-for-setting-flood-thresholds/how-to-measure-cps.html.

With that information in hand it was just a matter of time before working out how to collect this data through PRTG so do follow on with the screenshot guide to find out how!

Handy strings:
1.3.6.1.4.1.25461.2.1.2.3.10
[rowidentifier] Connections Per Second
TCP
UDP
Other IP

Some more information on Zone Protection/Flood Protection: https://docs.paloaltonetworks.com/pan-os/9-1/pan-os-web-interface-help/network/network-network-profiles/network-network-profiles-zone-protection/flood-protection.html