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Questions tagged [tunnel]

For questions about network tunnels.

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MTU - proactively setting to lower than 1500 on endpoints to prevent tunnel issues

With machines being deployed to various locations where internet is controlled by others, sometimes there can be one or two tunnels which necessitates using lower MTU to avoid communication issues, ...
g491's user avatar
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1 vote
1 answer
26 views

Inner header and Outer header in tunnel packet

What should be at Inner header and Outer header in tunnel packet ? And then we have tunnel IP address(for both router), tunnel source IP address, tunnel destination IP address. In my understanding, ...
jacky chong's user avatar
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1 answer
274 views

How to remote access CCTV's device behind CGNAT for IPv4, and device doesn't have support for DDNS IPv6? [closed]

TL;DR Multiple locations with local CCTV. How to remote access all of them, with an ISP that services IPv4 behind CGNAT and the DVR doesn't supports DDNS for IPv6. DVR also offers API, SDK, P2P and ...
Justcurious's user avatar
1 vote
2 answers
281 views

what is the purpose of GRE in UDP encapsulation if its unidirectional

I was going through this feature of GRE called GRE-in-UDP encapsulation. The RFC says it is unidirectional and the tunnel traffic is not expected to be returned back to the UDP source port values used ...
RootPhoenix's user avatar
0 votes
1 answer
276 views

VXLAN VNI VLAN mapping

Is VXLAN tunneling similar to Q-in-Q tunneling (except VxLAN works at Layer 3), such that each customer/tenant gets its own VNI and each VNI can then map to multiple VLANs, so a single VNI can ...
Haswell's user avatar
  • 115
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1 answer
71 views

On what basis does a router actually install GRE headers and remove them?

I am learning about networks and I have reached the topic of tunnels. At the same time, I have a need to set up a GRE (Generic Routing Encapsulation) tunnel between a remote server (to route addresses ...
Юрий Паршутин's user avatar
0 votes
1 answer
69 views

IPSec over L2GRE scenario

I wanted to know if this is a valid scenario and if it is possible to implement. There is a remote site A. and a Data center site B. Both A and B have a edge router which runs an IPSec tunnel. An ...
RootPhoenix's user avatar
0 votes
1 answer
24 views

Which technologies are most relevant for mobile broadband ISP bonding? [closed]

If I have edge router and core router (kind of Hub) and few ISP lines between them what are the most relevant technologies to be used for mobile broadband bonding? Expected result is: if one of ISP ...
baltasvejas's user avatar
0 votes
1 answer
289 views

DH groups support for isakmp policy

When configuring a site-to-site VPN tunnel between the ASA and Cisco router, I have queries around the ISAKMP policy. As per Cisco documentation for ASA, the crypto isakmp policy groups available are ...
Blake's user avatar
  • 57
0 votes
2 answers
344 views

IPsec PFS Confusion

I'm reading conflicting things about how PFS works in IPsec. Some sources say it's simply a renegotiation of the Phase 1 IKE/ISAKMP SA that ignores the original IKE/ISAKMP SA lifetime value and that ...
Ceejus's user avatar
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0 votes
1 answer
341 views

Can you sniff network traffic through a VPN tunnel? [closed]

Background: I am doing research for building an automated penetration testing application. All tests will be run from some server with a public IP ("testing server"). The objective is to ...
11ty1's user avatar
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0 votes
2 answers
959 views

GRE tunnel bridging and MTU mismatch

Background My workplace has 2 office areas which is only 200 meters away from each other. They have their own local networks, their own Internet connections, with routers configured to fallback to the ...
Livy's user avatar
  • 433
0 votes
2 answers
1k views

Why does recursive routing happen?

According to: https://study-ccnp.com/gre-tunnels-recursive-routing-problems/ Recursive routing occurs when the router learns the destination IP address for the tunnel interface through the tunnel ...
manish ma's user avatar
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0 votes
2 answers
672 views

Override tunnel-all VPN connection to print locally

We have a remote office with several users. The users connect to the cable modem there and individually VPN to our NSA2650 via Sonicwall Global VPN client. This client is set to tunnel-all mode ...
stack-exchange-is-ruined's user avatar
1 vote
3 answers
171 views

dynamic mac address added all hosts through the Do1Q tunnel

we have a nexus switch, we configure two customer ports in different switches with (mode Dot1Q tunnel) as all traffic must have two VLAN tags, an inner tag, and an outer tag, in our network, we ...
Anas Programmer's user avatar
1 vote
0 answers
86 views

Cisco L2TP VPNd with GRE over IPsec tunnel [closed]

I have a GRE over IPsec tunnel between router 1 and router 2. The routing between the 2 routers is EIGRP. I have access to the CLI and I can ping all subnets. I try to create VPNd L2TP I create it, ...
samer kareem's user avatar
2 votes
2 answers
700 views

In tunneling, how destination routers identify if a packet is encapsulated?

In tunneling, a packet gets encapsulated in the payload section of another packet. If the router at one end encapsulates the packet, then how the router at another end identifies whether the packet is ...
Allan's user avatar
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1 vote
1 answer
37 views

In PPTP, do encapsulated packets get further encapsulated in Ethernet frames?

I know that for PPP to travel in datalink layer 2 (ethernet) , the ppp frames need to get encapsulated in a ethernet frame , thus PPPoE. Is the same case for PPTP too?
Allan's user avatar
  • 107
2 votes
2 answers
847 views

Site-to-Site VPN with Sophos XG using tunnel interface

So I have configured a Sophos XG site-to-site vpn according to this document: https://docs.sophos.com/nsg/sophos-firewall/18.0/Help/en-us/webhelp/onlinehelp/nsg/sfos/learningContent/...
FloatingPointOperation's user avatar
4 votes
1 answer
1k views

Cisco IOS -> ASA VTI tunnel not routing traffic

I have a VTI tunnel configured between two devices (ASR and ASAv). The tunnel comes up fine and is stable, however traffic appears to be unidirectional, from the ASR -> ASAv but not in the reverse ...
btongeorge's user avatar
2 votes
1 answer
152 views

Transporting TRILL over Juniper QFX5100

I've got 2 Brocade VDX switches setup using VCS and want to add another 2 switches to this group, but when connected to each other over a Juniper QFX5100, they won't see each other. The Brocade ...
Marco's user avatar
  • 121
0 votes
2 answers
110 views

What are the benefits of using a transport label in L3VPN?

If not utilizing any form of TE (Traffic Engineering), are there any benefits of using a transport label in L3VPN - instead of just using a simple IPinIP tunnel? e.g. if traffic is egressing PE1 with ...
manish ma's user avatar
  • 1,644
0 votes
1 answer
81 views

Why does GRE tunnel has lesser TxBS/RxBS than its physical interface?

Given for instance, interface Tunnel200 tunnel destination 110.153.1.1 There's a static route for 110.153.1.1, pointing to physical interface Gi0/0. Gi0/0 is only used for tunnel200. Under show ...
iridescent's user avatar
4 votes
2 answers
1k views

MTU/MSS Oddness?

We have an IKEv2 IPSec tunnel between two Sophos XG Firewall appliances in a corporate system for a remote site. We don't have any specialized MSS or MTU settings other than what the IPSec tunnel ...
Thomas Ward's user avatar
0 votes
1 answer
70 views

What is a child tunnel? [closed]

I only heard this term today, but it was explained to me as a point-to-point VPN (so, two routers with a VPN tunnel established between them) and a firewall configured to only allow certain hosts to ...
leeand00's user avatar
  • 331
1 vote
0 answers
35 views

Segment Routing Encapsulation on Client Interface? [closed]

I wanted to test SRv6. Always between two clients (client 1 <-> client 2). If I do the encapsulation on the client everything works smooth as expected. Client 1 (encap SRv6 Tunnel) <- 2001::/...
user674907's user avatar
0 votes
1 answer
427 views

routing MTU size and encapsulation?

I did some research for my question beforehand such as this one:Cisco routers THROUGHPUT - MTU and packet size however, it seemed not precise to explain the doubts in my head. My primary goal is to ...
user53815's user avatar
  • 123
1 vote
3 answers
413 views

Combining NAT an tunneling

I was reading a text and a doubt came to mind. Suppose there is an interface in a router that implements NAT. That same interface is the extreme of a tunnel. If I was to send a message through said ...
shaymin shaymin's user avatar
1 vote
2 answers
51 views

How to build secure access for cloud machine in small startup [closed]

We have 7 member team (3 dev + 2 qa + 2 Sales). We host our PROD + QA + DEMO server in GCP. As of now, all our PROD/QA/DEMO/DEV/QA-DB/DEV-DB machine are having public IP, so that we can ssh into them. ...
Bhuvan's user avatar
  • 111
2 votes
1 answer
3k views

What's the difference between L2TP and L2TPv3? [closed]

Is L2TPv3 an improvement of L2TP or a completely different technology? Other than "it scales better" and "the non-proprietary MPLS" I can't find much information about it that's ...
Vita's user avatar
  • 195
1 vote
0 answers
23 views

Is it possible to gain VPN access through RDP [closed]

Scenario: I have been tasked to resolve an issue for a client's EmailReceiver program. I have the source code on my PC. I have been given RDP Access to a entry point machine, through which I can ...
Cornelis's user avatar
  • 111
6 votes
2 answers
1k views

Encapsulation: can a higher protocol encapsulate a lower protocol?

I've heard someone say that a protocol higher up the osi model can encapsulate a lower protocol. As far as I know, personally, a protocol can only encapsulate a same-level protocol or one at a ...
Daniel's user avatar
  • 333
0 votes
0 answers
1k views

Q-IN-Q Tunnel between cisco and mikrotik not work

i have try to make A Q-IN-Q tennel between two router (cisco and Microik) through cisco switch in mikrotik VLAN ID = 10 IN interface ether1 VLAN ID = 20 in interaface Vlan10 ip address in interface ...
Anas Programmer's user avatar
1 vote
2 answers
75 views

What does a VPN Tunnel offers other than encryption?

A VPN tunnel is end to end encrypted. But does it gurantee to provide features other than encryption, such as low latency, low jitter etc?
Rumesh Madhusanka's user avatar
2 votes
1 answer
214 views

Confusion about IANA "Protocol Numbers" registery

In the IANA registery for "Protocol Numbers", there listed 2 IP protocol versions: IPv4 at #4 and IPv6 at #41. Their "protocol" column says IPv[46] Encapsulation, and "...
DannyNiu's user avatar
  • 173
0 votes
1 answer
227 views

PPTP encapsulation process

i am learning networking and vpn technologies now and i have some problems with understanding the whole PPTP encapsulation process. So i will write steps of PPTP encapsulation process (as i understand ...
violetapple's user avatar
0 votes
1 answer
81 views

GRE Encapsulation

i am learning networks and tunneling and i have problems with understanding some things about GRE. The structure of tunneling below: [Transport Protocol][ensapsulationg protocol(GRE)][encapsulateed ...
violetapple's user avatar
1 vote
1 answer
180 views

Finding MSS for a remote connection that uses tunnelling

I'm working on a codebase where we're trying to test network health by verifying if we can ping the remote site having payload = MSS without any packet fragmentation (using -df flag). Typically, for ...
Ashutosh's user avatar
  • 113
0 votes
1 answer
49 views

IP-Sec VPN Tunnel Established Between 2 Remote Machines. Why Can't Machines In Their Subnets Connect Across? [closed]

Have 2 Remote Ubuntu Machines in different subnets. one: 192.168.1.0/24 Two: 192.168.2.0/24 Established VPN tunnel between 2 machines, 1 in each subnet. Their IPs: Public IPs 1.1.1.1 2.2.2.2 ...
user avatar
0 votes
1 answer
2k views

Cisco qos, service-policy on output interface on 1100 ISR seems ignored

I am trying to configure QoS for a specialty purpose application, and it is the first time I have done QoS. This is on an 1100 ISR with IOS XE 16.09.03. The device is a set of 4 that establish a mesh ...
Linwood's user avatar
  • 227
0 votes
1 answer
57 views

VPN to a current subnet ID

I am sure this is a fairly basic question, but the standard google searches have not told me what I am looking for. I have a restaurant that uses an ipad point of sale on a dedicated subnet id: 192....
Andy Latham's user avatar
1 vote
1 answer
326 views

Tacacs+ over VPN is not working

R3 is a Tacacs+ client and Server0 is configured as AAA server with Tacacs+ but R3 is not able to authenticate. R3 Configuration: ! version 15.4 no service timestamps log datetime msec no service ...
Reshad Zazai's user avatar
0 votes
1 answer
688 views

What is the difference between VPN and Domain fronting?

What is Domain fronting? and how it is different from a VPN?
maysara's user avatar
  • 103
0 votes
1 answer
1k views

How can I accomplish VPN across Dual Wan connections?

How can I accomplish VPN across Dual Wan connections in a optimal way? Idea is to make: Site to site VPN. Make single connection inside the VPN to use full bandwidth of both wan connections using (...
shore's user avatar
  • 1
0 votes
1 answer
2k views

How do you define interesting traffic using an IPSec Profile on a Cisco router?

I apologize if this is a duplicate, but I'm having difficulty figuring out how to define interesting traffic on a Cisco router using an IPSec Profile referenced by a tunnel interface. The old-school ...
DragonFist616's user avatar
1 vote
1 answer
124 views

Assign a new public and static IP to a router behind my main router [closed]

What can you suggest to bring a second public and static IPv4 so I can configure my WAN-A interfase with my primary and an additional secondary IP settings so I can route all the traffic from the ...
Ovidio Vazquez's user avatar
1 vote
1 answer
2k views

Dropping packets between router and firewall without firewall rule

I have a user that is trying to access his company network resources on his home network. He is able to access SMB shares and other resources, but he is unable to access their AS400 on any computer in ...
Josh Eblin's user avatar
3 votes
2 answers
22k views

VPNs are working in which layer of the OSI model? [closed]

As the following picture shows, it is possible to categorize VPNs in two general categories: Client-based VPNs Network-based VPNs When it is required to choose a VPN for implementation in a network, ...
R1w's user avatar
  • 311
0 votes
1 answer
509 views

Remote access to the network without port forwarding (blocked by ISP) - VPN [closed]

I need to setup a following configuration: A router Mikrotik is connected to the internal Network1. The router has a USB 3G modem that is connected to it and enables internet access from the ...
Adam Wolski's user avatar
0 votes
1 answer
1k views

qos inside vpn, possible or not ? I read yes and no

I am wondering if possible to do QOS (or similar action) inside vpn tunnel to a cloud server. the goal is to reserved bandwith for voip traffic. I read that you can with GRE and other people said, ...
svi08wi0er92u30r's user avatar