Secure network designs Flashcards
What is another function of a load balancer other than just…. balancing the load?
TCP/SSL offload.
You can offset some of the protocol/encryption overheard by having the load balancer deal
In load balancing, what is round-robin?
Round robin is a method of load balancing in which the load is distributed completely evenly across all servers by sending each request to a different server in order. Request 1-->server 1 Request 2-->server 2 Request 3-->server 3 Request 4-->server 1 Request 5-->server 2
There is also such a thing as a “Weighted round-robin” where certain servers are prioritized over others, example: half of the requests will go to server 1, the other half will be distributed between servers 2-5.
“Dynamic round-robin” also exists, which is monitoring the server load and always giving traffic to the server which currently has the lowest use.
What is active/active load balancing?
All servers are active at the same time.
If one server fails, another will take over its load.
In load balancing what is affinity/sticky session/session persistence?
This is a way of ensuring that each user is stuck to the same server in load balancing scenarios. Typically tracked through IP address or session IDs
Many applications require communication to the same instance.
What is active/passive load balancing?
This is when certain servers are active, and others are on standby.
If one of the active servers goes down or stops functioning, one of the standby servers will activate and start taking on the load in place of the downed server.
What are the 3 types of network segmentation?
Physical, logical, and virtual.
What is physical segmentation?
This is also called an air gap.
This is where devices are physically seperate.
Like an air gap between Switch A and Switch B.
Two devices have no connection to each other physically.
What is logical segmentation?
Logical segmentation is almost always associated with VLANs.
This is a way of logically splitting up a switch to support two different networks, where they can not communicate with each other without a layer 3 device/router.
Basically splitting up a device and doing a segmentation on one device instead of creating an air gap.
What is a screened subnet?
THINK DMZ(demilitarized zone), they don't call it that anymore. This is an additional subnet hidden behind a firewall to separate a more sensitive network(probably your company's internal corporate network) from a public facing service that users are connecting to from the outside internet. All of the traffic coming from the external internet will be forwarded to the "screened subnet" rather than your internal network.
What is an extranet?
This is a seperate network set up for vendors, suppliers, and other partners that need access to your internal resources.
Unlike a screened subnet an extranet typically requires additional authentication.
You would typically get a login screen or something when trying to access an extranet from the internet, and if you authenticated, then you would be granted access to the extranet.
Similar to a screened subnet, they are split up by a firewall.
What is an intranet?
Intranets are only accessible from inside the network.
This has no external access, you can only get in internally or through a VPN.
Typically houses work related documents needed for an organization.
What is the difference between east-west traffic and north-south traffic?
This is almost exclusively referring to traffic flowing inside of a data center.
East-west traffic is going between devices in the same data center and is able to achieve relatively fast response times.
North-south traffic is either inbound or outbound from our data center and typically will have different security policies associated with it.
What is a VPN?
Really explain
A VPN is a way to send data securely through an area that would normally be considered public without anyone in the middle being able to understand anything that is being said.
An encrypted tunnel.
What is a concentrator in regards to VPNs?
When you connect to your corporate network using their vpn, you will be connecting to this device and it will middleman your conversations.
This is the device doing the heavy lifting with regards to VPNs.
This device handles all of the encrypting and sending out data, and decrypting anything that it happens to receive.
Often a standalone device or built into a firewall. There are also software based options available (nordvpn, etc)
These are almost always used though with some kind of client software for making it all happen, sometimes there can be something built into your OS for handling vpn connections.
What is an SSL VPN?
A VPN that uses SSL/TLS, and communicates on tcp port 443 (think https(http secure, HTTPS, SSL/TLS, get it?)
You don’t need any big vpn clients, it is able to authenticate users with no requirement for digital certificates, and can be run from a browser or from a (usually light) VPN client.
What is an HTML5 VPN?
This is a VPN that takes advantage of the recent upgrade to HTML to version 5.
HTML5 supports APIs and it comes built in with a web cryptography API, which makes you able to create an encrypted VPN tunnel without the need for a separate VPN application, and can instead do it completely from your browser using HTML. Nothing to install.
You do need to make sure you have a browser that can support HTML5.
