37
votes
Accepted
Why use SSH and VPN in combination?
The reasoning behind your current setup is probably some combination of the following three reasons.
The VPN is a security solution for outside your company's network (See #1 below). SSH however, ...
- 551
22
votes
Why use SSH and VPN in combination?
SSH is an extremely popular target for brute-forcing attempts. If you have an SSH server directly on the Internet, within minutes, you will see login attempts with all kinds of user names (and ...
- 489
16
votes
Accepted
In IPsec VPN, how is the pre-shared key encrypted?
You've asked a great question. The question seems very simple, but in fact the answer is somewhat more complex. I'll do my best to answer it in a succinct manner. Also, since you mentioned ISAKMP, ...
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15
votes
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Why would a VPN require a T1?
First of all, T1 gives you around 1.5Mbit/s in both directions, not 3Mbit/s. If you're seeing 3Mbit/s, it may be bundled from two separate lines.
Now, for VPN, if that's IP-based VPN as 99% of VPNs ...
- 4,010
11
votes
Accepted
netstat -nr returning "0/1" -- what does that mean?
Some VPNs push the default gateway (a /0 netmask) as two /1 networks: 0/1 and 128/1. Since a more specific route always wins, this forces traffic to be routed via the VPN instead of over the default ...
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10
votes
How can I reset a VPN tunnel on a Cisco ASA?
I just came across a new way that I was never aware of before and offers the same information you find in the ASDM interface, including the feature to logoff a vpn session.
Issue this for example to ...
- 201
10
votes
Why would a VPN require a T1?
There is no technical reason for requiring a leased line or similar for the VPN if another (cheaper) option is adequately fast and sufficiency low latency.
It may be that the leased line comes with ...
- 201
8
votes
Accepted
Backup IP for site 2 site VPN (Juniper SRX)
Junos does have DPD and you can use it in conjunction with multiple endpoint IP addresses in a single IKE tunnel.
There is a bit of info about it here (which I've copied below)
http://kb.juniper.net/...
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8
votes
PPPoE vs L2TP protocols
The most and noticeable different is layer of tunneling. PPPOE is a Layer 2 (Data Link Layer) tunneling protocol while L2TP is a Layer 3 (Network Layer) tunneling protocol. This means that PPPOE can ...
- 258
8
votes
Accepted
Is VPN a layer 3 concept?
There are layer-2 and layer-3 VPNs. "VPN" is a term used for a tunnel combined with encryption.
A tunneling interface encapsulates an inner packet (or frame) in an outer packet. This inner ...
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7
votes
Accepted
Routing protocol for Large scale hub and spoke VPN
I think BGP is probably your best bet in this situation. The number of tail sites you have quickly exceeds the benefits of most IGPs. BGP would allow you to achieve all of your desired ...
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7
votes
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Cisco ASA VPN with split-dns on a Windows VPN client
Experiment
There is a lot of conflicting information about what actually happens on a Windows client when using split-dns. So much that I decided to gather some evidence and see where it points. I ...
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7
votes
Why would a VPN require a T1?
Why can't we just put a VPN on a normal cable connection?
You can. I VPN to the office from my phone reasonably frequently.
What technology you use for the transport layer is ultimately irrelevant: ...
7
votes
Why use SSH and VPN in combination?
The VPN allows you to connect to your employer's private network and acquire an IP address of that private network. Once you're connected to the VPN, it's like you are using one of the computers ...
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7
votes
IPSec based VPN using Openswan - IP confusion
Most of your answers can be found here:
http://linux.die.net/man/5/ipsec.conf
To speak through them however:
left will specify the IP address of the left peer, as it is seen from the right peer. ...
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7
votes
Accepted
How do VPN's forward network traffic? (Layer 3)
Take for example the GRE-Header (GRE is a protocol used to realize VPNs - its not often used as its not secure in any way, but the concept with encapsulation is nearly the same in every VPN connection ...
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7
votes
Difference between WAN and VPN(tunnels)
Originally, WANs were mostly defined by specific layer 1/2 protocols (Frame Relay, HDLC, SONET, etc) that they used, but Ethernet has taken over, and the others are rapidly fading into history. The ...
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7
votes
Accepted
Why is VPN not a protocol?
A protocol is a set of rules for how to accomplish something, and network protocols are sets of rules for how to communicate on a network.
VPN is a concept, and a VPN uses protocols to accomplish the ...
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6
votes
Accepted
Cisco IPSEC VPN fail Stage 2
Access lists aren't a problem here.
The output from show cypro isakmp sa tells you that the key negotiation is failing (MM_NO_STATE).
The log entry says that the hub wants to use a transform set (...
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6
votes
Accepted
Can we change peer IP of IPSec VPN tunnel in one line?
Can I change that simply by typing the following in conf t:
In your example, issuing crypto map Outside_map 10 set peer 0.9.8.7 6.5.4.3 will append 0.9.8.7 6.5.4.3 to your existing peer list for ...
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6
votes
In MPLS VPN, Which one become first? MPLS Label tag or VPN encapsulation?
I think your question is not truly correct.
First of all, as explain here
"an MPLS VPN is a VPN that is built on top of an MPLS network, usually from a service provider, to deliver connectivity ...
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6
votes
Confused on perfect forward secrecy, someone kindly help me
The link you provided was broken, so I couldn't validate the context.
But, as I contributed to the other thread, I might be in a good place to help contribute to this =).
At the end of ISAKMP (Phase ...
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6
votes
How do VPN's forward network traffic? (Layer 3)
So the short answer to your question is encapsulation. Meaning there is another set of packet headers put around the packet you are sending to a website that is taken off by the VPN endpoint.
Think ...
- 81
5
votes
How can I connect two different locations through our ISP?
IPSec VPN
Virtual Private Network (VPN) over the Internet with IPSec protocols for authentication and encryption. Using a Firewall w/VPN is typical here. A hub-and-spoke model is generally deployed....
- 6,999
5
votes
Accepted
Split Horizon, and mGRE/NHRP
The split horizon rule is essentially:
Don't advertise a route out of the same interface you learned it from.
With hub and spoke networks and mGRE, the hub is connected to the spokes by a single (...
- 62.1k
5
votes
In IPsec VPN, how is the pre-shared key encrypted?
Your answer is in your question: The Diffie-Hellman exchange is used to generate a common key to securely exchange a common key (i.e. pre-share).
See this: https://security.stackexchange.com/...
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5
votes
Accepted
After upgrading ASA, client VPN failing from site with active LAN to LAN tunnel
Yes, the device can be instructed to accept the client VPN connections from the peer that it already has an open tunnel with.
This is done by updating the dynamic map to include new entries with a ...
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5
votes
Accepted
Does all IP traffic go throught a SSL VPN?
This is a feature that most VPN platforms have. It's called 'split-tunneling'.
And this is up to the VPN administrator. Some decide to send all traffic through the VPN tunnel and others don't.
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5
votes
Does IPv6 remove the need for a VPN?
The primary point of IPv6 is that it restores the original idea of every device having a unique IP address, which restores the end-to-end concept of IP. NAT is a kludge to extend the life of IPv4 ...
- 92.9k
5
votes
Accepted
What is OpenVPN?
OpenVPN is both - software (access server and client) and protocol. The protocol uses TLS-encrypted UDP or TCP for transport. It can provide routed or bridged connections. OpenVPN can be used for ...
- 69.7k
Only top scored, non community-wiki answers of a minimum length are eligible