Autosave: 2025-02-24 18:05:00

neuron/5b69d72b-62b5-4e7c-a093-2115c3fe6538/How_tunneling_works_with_VPNs.md

@@ -0,0 +1,29 @@
+---
+tags: [networks, VPN]
+created: Monday, February 24, 2025
+---
+
+# How tunnelling works with VPNs
+
+A VPN is a good example of a [network tunnel](Network_tunnels.md) and the
+technique of packet wrapping / encapsulation to bypass network restrictions.
+
+When a user connects to a VPN, their device creates a connection to the VPN
+server. All subsequent traffic is routed first through the tunnel, rather than
+directly to the target host IP.
+
+When the data arrives at the VPN server, the VPN wraps the packets inside new
+packets that have the VPN server's addressing information. The nested packets
+are encrypted before they are encapsulated and the tunnel they arrive through is
+also encrypted end-to-end. Thus there is - in theory - no way to know where the
+original packets come from.
+
+When the data returns from the target host to the VPN server that requested it,
+the VPN server decrypts the data and forwards it back through the secure tunnel
+to the original user's device.
+
+Whilst connected to the VPN, the user's IP appears to be identical to the IP of
+the VPN server. This is because the outer packet header has the VPN's addressing
+information, not the source IP's (this is encrypted within the payload). As the
+target host only sees the VPN's headers, it appears as if the VPN user's IP is
+the same as the VPN's.

neuron/5b69d72b-62b5-4e7c-a093-2115c3fe6538/Network_tunnels.md

@@ -0,0 +1,28 @@
+---
+tags: [networks, VPN]
+created: Monday, February 24, 2025
+---
+
+# Network tunnels
+
+A network tunnel is a
+[Transport Layer](Transport_Layer_of_Internet_Protocol.md) mechanism whereby
+data packets can travel across a network they would otherwise not be able to
+access. Similarly how an underground physical tunnel can be use to travel across
+an inaccessible geographic region.
+
+It is a broad concept of which there are various specific instances. However
+many involve creating a tunnel by wrapping a packet that cannot traverse a given
+network within the payload of a packet that can.
+
+For instance, an organisation may use [IPv6](IP_addresses.md) addresses but
+want to send them over an IPv4 network. To achieve this they would enclose the
+packets within IPv4 packets.
+
+Similarly the scenario of a VPN. A user with a UK IP address wants to access a
+server in the US that has a firewall blocking non-US IPs. The user can bypass
+this restriction by connecting to a VPN running US servers. The UK packets are
+transferred under the aegis of the VPN's US IP.
+
+For more detail see
+[How tunnelling works with VPNs](How_tunneling_works_with_VPNs.md).

neuron/5b69d72b-62b5-4e7c-a093-2115c3fe6538/index.md

@@ -13,12 +13,14 @@ computer science.
 
 <a href="https://thomasabishop.github.io/eolas/tags">View tags</a>
  
-**Build ID:** 44f350ea-f6e5-4cdc-865c-2119ac043cfa
+**Build ID:** 5b69d72b-62b5-4e7c-a093-2115c3fe6538
 
-**Published:** Sat 22 Feb 2025 14:52:09
+**Published:** Mon 24 Feb 2025 18:04:55
 
 ### Recent edits 
 
+- [[How_tunneling_works_with_VPNs]] 
+- [[Network_tunnels]] 
 - [[Capturing_program_error_in_Bash]] 
 - [[Check_if_value_null_in_Bash]] 
 - [[Associative_arrays_maps_in_Bash]] 
@@ -29,11 +31,9 @@ computer science.
 - [[Setup encrypted harddrive]] 
 - [[Disk_size_utilities]] 
 - [[Let's_Encrypt]] 
-- [[Certificate_authorities]] 
-- [[HTTPS]] 
 
 
-### All notes (533) 
+### All notes (535) 
 
 - [[0716531c_rewilding_the_internet]] 
 - [[241fe1a3_the_Web_versus_modem_BBSs]] 
@@ -256,6 +256,7 @@ computer science.
 - [[Headless_Raspi_network_setup]] 
 - [[Heap_memory]] 
 - [[Hexadecimal_number_system]] 
+- [[How_tunneling_works_with_VPNs]] 
 - [[ICMP_Protocol]] 
 - [[IP_addresses]] 
 - [[Identify_merged_branches]] 
@@ -355,6 +356,7 @@ computer science.
 - [[Network_protocols]] 
 - [[Network_requests_in_Python]] 
 - [[Network_scanning]] 
+- [[Network_tunnels]] 
 - [[NodeJS_scripts]] 
 - [[Node_and_MySQL_db]] 
 - [[Nodemon]] 

neuron/5b69d72b-62b5-4e7c-a093-2115c3fe6538/tags.md

@@ -4,7 +4,7 @@ unlisted: true
 ---
 
 # Tags
-[algebra](./tags#algebra), [algorithms](./tags#algorithms), [analogue](./tags#analogue), [android](./tags#android), [APIs](./tags#APIs), [arch-linux](./tags#arch-linux), [arithmetic](./tags#arithmetic), [ARPA](./tags#ARPA), [ARPANET](./tags#ARPANET), [awk](./tags#awk), [AWS](./tags#AWS), [aws-lambda](./tags#aws-lambda), [binary](./tags#binary), [bulletin-boards](./tags#bulletin-boards), [bus](./tags#bus), [C](./tags#C), [computer-architecture](./tags#computer-architecture), [computer-history](./tags#computer-history), [containerization](./tags#containerization), [CPU](./tags#CPU), [cryptography](./tags#cryptography), [csv](./tags#csv), [data-structures](./tags#data-structures), [data-types](./tags#data-types), [databases](./tags#databases), [design-patterns](./tags#design-patterns), [disks](./tags#disks), [docker](./tags#docker), [dynamodb](./tags#dynamodb), [ecopolsoc](./tags#ecopolsoc), [electricity](./tags#electricity), [electromagnetism](./tags#electromagnetism), [electronics](./tags#electronics), [encryption](./tags#encryption), [exponents](./tags#exponents), [file-system](./tags#file-system), [firewalls](./tags#firewalls), [fleeting](./tags#fleeting), [fractions](./tags#fractions), [git](./tags#git), [graphql](./tags#graphql), [hardware](./tags#hardware), [IaC](./tags#IaC), [internet](./tags#internet), [javascript](./tags#javascript), [jest](./tags#jest), [json](./tags#json), [JSON](./tags#JSON), [kernel](./tags#kernel), [Linux](./tags#Linux), [linux](./tags#linux), [literature](./tags#literature), [logic](./tags#logic), [logic-gates](./tags#logic-gates), [memory](./tags#memory), [Microsoft](./tags#Microsoft), [middleware](./tags#middleware), [modems](./tags#modems), [mongo-db](./tags#mongo-db), [mongoose](./tags#mongoose), [nand-to-tetris](./tags#nand-to-tetris), [network-protocols](./tags#network-protocols), [networks](./tags#networks), [node-js](./tags#node-js), [number-systems](./tags#number-systems), [number-theory](./tags#number-theory), [OOP](./tags#OOP), [operating-systems](./tags#operating-systems), [packet-switching](./tags#packet-switching), [physics](./tags#physics), [ports](./tags#ports), [prealgebra](./tags#prealgebra), [privacy](./tags#privacy), [procedural](./tags#procedural), [propositional-logic](./tags#propositional-logic), [proxies](./tags#proxies), [python](./tags#python), [question](./tags#question), [raspberry-pi](./tags#raspberry-pi), [react](./tags#react), [recursion](./tags#recursion), [regex](./tags#regex), [REST](./tags#REST), [S3](./tags#S3), [server-management](./tags#server-management), [set-theory](./tags#set-theory), [shell](./tags#shell), [SNS](./tags#SNS), [sound](./tags#sound), [SQL](./tags#SQL), [SQLite](./tags#SQLite), [SQS](./tags#SQS), [ssh](./tags#ssh), [storage](./tags#storage), [surveillance-capitalism](./tags#surveillance-capitalism), [systemd](./tags#systemd), [systems-programming](./tags#systems-programming), [testing](./tags#testing), [theorems](./tags#theorems), [theory-of-computation](./tags#theory-of-computation), [time](./tags#time), [TOR](./tags#TOR), [Turing](./tags#Turing), [typescript](./tags#typescript), [unix](./tags#unix), [world-wide-web](./tags#world-wide-web), [yaml](./tags#yaml), 
+[algebra](./tags#algebra), [algorithms](./tags#algorithms), [analogue](./tags#analogue), [android](./tags#android), [APIs](./tags#APIs), [arch-linux](./tags#arch-linux), [arithmetic](./tags#arithmetic), [ARPA](./tags#ARPA), [ARPANET](./tags#ARPANET), [awk](./tags#awk), [AWS](./tags#AWS), [aws-lambda](./tags#aws-lambda), [binary](./tags#binary), [bulletin-boards](./tags#bulletin-boards), [bus](./tags#bus), [C](./tags#C), [computer-architecture](./tags#computer-architecture), [computer-history](./tags#computer-history), [containerization](./tags#containerization), [CPU](./tags#CPU), [cryptography](./tags#cryptography), [csv](./tags#csv), [data-structures](./tags#data-structures), [data-types](./tags#data-types), [databases](./tags#databases), [design-patterns](./tags#design-patterns), [disks](./tags#disks), [docker](./tags#docker), [dynamodb](./tags#dynamodb), [ecopolsoc](./tags#ecopolsoc), [electricity](./tags#electricity), [electromagnetism](./tags#electromagnetism), [electronics](./tags#electronics), [encryption](./tags#encryption), [exponents](./tags#exponents), [file-system](./tags#file-system), [firewalls](./tags#firewalls), [fleeting](./tags#fleeting), [fractions](./tags#fractions), [git](./tags#git), [graphql](./tags#graphql), [hardware](./tags#hardware), [IaC](./tags#IaC), [internet](./tags#internet), [javascript](./tags#javascript), [jest](./tags#jest), [json](./tags#json), [JSON](./tags#JSON), [kernel](./tags#kernel), [Linux](./tags#Linux), [linux](./tags#linux), [literature](./tags#literature), [logic](./tags#logic), [logic-gates](./tags#logic-gates), [memory](./tags#memory), [Microsoft](./tags#Microsoft), [middleware](./tags#middleware), [modems](./tags#modems), [mongo-db](./tags#mongo-db), [mongoose](./tags#mongoose), [nand-to-tetris](./tags#nand-to-tetris), [network-protocols](./tags#network-protocols), [networks](./tags#networks), [node-js](./tags#node-js), [number-systems](./tags#number-systems), [number-theory](./tags#number-theory), [OOP](./tags#OOP), [operating-systems](./tags#operating-systems), [packet-switching](./tags#packet-switching), [physics](./tags#physics), [ports](./tags#ports), [prealgebra](./tags#prealgebra), [privacy](./tags#privacy), [procedural](./tags#procedural), [propositional-logic](./tags#propositional-logic), [proxies](./tags#proxies), [python](./tags#python), [question](./tags#question), [raspberry-pi](./tags#raspberry-pi), [react](./tags#react), [recursion](./tags#recursion), [regex](./tags#regex), [REST](./tags#REST), [S3](./tags#S3), [server-management](./tags#server-management), [set-theory](./tags#set-theory), [shell](./tags#shell), [SNS](./tags#SNS), [sound](./tags#sound), [SQL](./tags#SQL), [SQLite](./tags#SQLite), [SQS](./tags#SQS), [ssh](./tags#ssh), [storage](./tags#storage), [surveillance-capitalism](./tags#surveillance-capitalism), [systemd](./tags#systemd), [systems-programming](./tags#systems-programming), [testing](./tags#testing), [theorems](./tags#theorems), [theory-of-computation](./tags#theory-of-computation), [time](./tags#time), [TOR](./tags#TOR), [Turing](./tags#Turing), [typescript](./tags#typescript), [unix](./tags#unix), [VPN](./tags#VPN), [world-wide-web](./tags#world-wide-web), [yaml](./tags#yaml), 
 
 ### algebra 
 
@@ -685,6 +685,7 @@ unlisted: true
 - [[f0f70a3c_ARPANET_motivations]] 
 - [[Firewalls]] 
 - [[Headless_Raspi_network_setup]] 
+- [[How_tunneling_works_with_VPNs]] 
 - [[ICMP_Protocol]] 
 - [[Internet_fundamentals]] 
 - [[Internet_Layer_of_Internet_Protocol]] 
@@ -700,6 +701,7 @@ unlisted: true
 - [[Network_protocols]] 
 - [[Network_requests_in_Python]] 
 - [[Network_scanning]] 
+- [[Network_tunnels]] 
 - [[Peer_to_peer_network]] 
 - [[Ping]] 
 - [[Proxies]] 
@@ -1206,6 +1208,10 @@ unlisted: true
 ### unix 
 
 - [[Time_and_computers]] 
+### VPN 
+
+- [[How_tunneling_works_with_VPNs]] 
+- [[Network_tunnels]] 
 ### world-wide-web 
 
 - [[241fe1a3_the_Web_versus_modem_BBSs]] 

zk/How_tunneling_works_with_VPNs.md

@@ -0,0 +1,29 @@
+---
+tags: [networks, VPN]
+created: Monday, February 24, 2025
+---
+
+# How tunnelling works with VPNs
+
+A VPN is a good example of a [network tunnel](./Network_tunnels.md) and the
+technique of packet wrapping / encapsulation to bypass network restrictions.
+
+When a user connects to a VPN, their device creates a connection to the VPN
+server. All subsequent traffic is routed first through the tunnel, rather than
+directly to the target host IP.
+
+When the data arrives at the VPN server, the VPN wraps the packets inside new
+packets that have the VPN server's addressing information. The nested packets
+are encrypted before they are encapsulated and the tunnel they arrive through is
+also encrypted end-to-end. Thus there is - in theory - no way to know where the
+original packets come from.
+
+When the data returns from the target host to the VPN server that requested it,
+the VPN server decrypts the data and forwards it back through the secure tunnel
+to the original user's device.
+
+Whilst connected to the VPN, the user's IP appears to be identical to the IP of
+the VPN server. This is because the outer packet header has the VPN's addressing
+information, not the source IP's (this is encrypted within the payload). As the
+target host only sees the VPN's headers, it appears as if the VPN user's IP is
+the same as the VPN's.

zk/Network_tunnels.md

@@ -0,0 +1,28 @@
+---
+tags: [networks, VPN]
+created: Monday, February 24, 2025
+---
+
+# Network tunnels
+
+A network tunnel is a
+[Transport Layer](./Transport_Layer_of_Internet_Protocol.md) mechanism whereby
+data packets can travel across a network they would otherwise not be able to
+access. Similarly how an underground physical tunnel can be use to travel across
+an inaccessible geographic region.
+
+It is a broad concept of which there are various specific instances. However
+many involve creating a tunnel by wrapping a packet that cannot traverse a given
+network within the payload of a packet that can.
+
+For instance, an organisation may use [IPv6](./IP_addresses.md) addresses but
+want to send them over an IPv4 network. To achieve this they would enclose the
+packets within IPv4 packets.
+
+Similarly the scenario of a VPN. A user with a UK IP address wants to access a
+server in the US that has a firewall blocking non-US IPs. The user can bypass
+this restriction by connecting to a VPN running US servers. The UK packets are
+transferred under the aegis of the VPN's US IP.
+
+For more detail see
+[How tunnelling works with VPNs](./How_tunneling_works_with_VPNs.md).