Questions tagged [ipsec]

Internet Protocol Security (IPsec) is a protocol suite for securing Internet Protocol (IP) communications by authenticating and encrypting each IP packet of a communication session. IPsec also includes protocols for establishing mutual authentication between agents at the beginning of the session and negotiation of cryptographic keys to be used during the session.

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65
votes
8answers
120k views

What is the difference in security between a VPN- and a SSL-connection?

I would like to design a client-server application where the server is placed on Internet. I assume that I could set up the client-server connection using VPN (is it using IPSec?) or using a SSL ...
33
votes
6answers
64k views

Are there any reasons for using SSL over IPSec?

is it recommended to use both protocols together? In which situation?
24
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4answers
4k views

IPsec (Internet Protocol Security) facts

Internet Protocol Security (IPsec) is a successor of the ISO standard Network Layer Security Protocol (NLSP). What are the advantages, disadvantages, other interesting facts regarding the protocol?
17
votes
2answers
26k views

Which is better for server-to-server-communication: IPSec or TLS?

Maybe you could help me with a small problem. Would you recommend IPSec or TLS for a Server-to-Server-Connection? I need two or three arguments for reasoning a decision within my final paper, but ...
15
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5answers
802 views

What is the potential impact of the alleged OpenBSD IPSEC attack?

Recently there is a bit of concern over encryption back doors in IPsec and while the status of this has not been confirmed, I don't know what impact something like this might have. For instance, does ...
15
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3answers
17k views

What is the difference between SSH and IPsec?

There seems to be similar encryption going into both. They both use asymmetric (RSA, elliptic curves, etc) for the initial key exchange, then go to some symmetric (AES, Blowfish, etc) protocol. I'm ...
15
votes
1answer
4k views

If an attacker is intercepting all of my traffic, will he be able to listen on my VPN session?

If I am a remote user, connecting to my firm from home, using IPSec VPN tunnel or through SSL, and an attacker is intercepting all of my traffic, will he be able to watch my VPN session on the clear (...
14
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1answer
2k views

What's are the advantages of L2TP/IPSEC over plain IPSEC?

As the title says, my firewall (Sonicwall) can do either IPSEC or L2TP/IPSEC for VPN connections. One advantage of L2TP/IPSEC I can see is that the client computer get allocated its own IP address on ...
12
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5answers
19k views

Does IPSec use IKE or ISAKMP?

Does the IPSec protocol suite use IKE or ISAKMP? RFC 2828 states ISAKMP is the protocol used in IPSec to handle SAs, key management and system authentication. Other sources say IKE is the protocol ...
11
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3answers
4k views

How you can trust your Router to not steal your private IPSec keys?

I would like to connect to my VPN using IPSec protocol. For that, I need a router or any other device that support it. I found this on eBay: https://www.ebay.com/itm/IPsec-VPN-server-military-secure-...
11
votes
3answers
29k views

When do I use IPsec tunnel mode or transport mode?

I basically understand how tunnel mode and transport mode works, but I don't know when I should use one instead of another. Among the two parties who want to communicate, if one computer B doesn't ...
10
votes
7answers
3k views

How can I restrict access to network data by an unauthorized computer that connects via Ethernet?

I assume I can configure most routers to only assign IP addresses to specific MAC addresses, as is possible with wireless routers. However what if a computer is connected via Ethernet and does not ...
10
votes
2answers
15k views

which diffie-hellman group is needed for secure ike/ipsec

We're deploying ipsec on embedded devices and getting catastrophic performance from the diffie hellman 2048 group in ike.. afterwards the shared securet is used for 3des, sha1. ipsec negiation is ...
10
votes
4answers
14k views

How do I encrypt the source and destination IP address, along with various parts of an email?

If the subject makes no sense to you, that's fine, it makes no sense to me. I've been tasked with securing emails sent from some devices, and I'm looking for advice on intelligent questions to ask to ...
10
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2answers
24k views

Ipsec Native VPN on Windows 8 or 10

I have a Cisco PIX, and have been using the Cisco VPN client on windows however I would like to enable this to work with the native Windows 8/10 VPN client. It works fine with the native clients for ...
10
votes
2answers
256 views

Using certificates to secure

I'm working on an application that comprises of a C# WebAPI (on Azure Websites) and a native mobile app. Essentially, a client creates a series of messages using a Web interface and these can be ...
9
votes
2answers
1k views

Does DNSSec have any benefit if used with IPSec-enabled IPv6?

I'm not sure if the RFC's support a IPSec-only implementation of DNS, but if it does, what does that mean for DNSSec? Is DNSSec an IPv4-only technology?
9
votes
1answer
679 views

Maximum number of nodes with IPSec?

From my understanding, for incoming packets over IPSec, the Security Association (SA) is identified by the SPI field of the ESP header. Then let's say I have a bunch of nodes where each node wants to ...
8
votes
3answers
4k views

What is the difference between encrypted data and data sent through an encrypted tunnel?

I am looking at different VPN protocols. L2TP does not provide encryption so require IPSec to encrypt the data IPSec tunnel provide encryption to the tunnel What is the difference in terms of the ...
8
votes
1answer
3k views

How secure is L2TP+IPSEC?

I understand PPTP is widely used still, but insecure. A convenient alternative is: L2TP+IPSEC. How secure is it? What steps in the server setup can I take to maintain a high degree of compatibility ...
7
votes
2answers
15k views

Diffie Hellman Group Matching to IPSec Encryption Algorithm

I'm looking for help determining acceptable Diffie Hellman (DH) Groups for specific IPSec IKE and ESP Encryption Algorithms. The goal is to choose DH groups that provide adequate protection for the ...
7
votes
1answer
854 views

Is PSK-protected IKEv2 secure against MITMs?

I've set up an IKEv2 VPN connection as an alternative to an HTTP proxy (since HTTP proxies' credentials fly in plaintext and iOS still can't correctly remember proxy credentials) and I'd like to know ...
6
votes
5answers
900 views

Does mixing different types of encryption make the connection more secure?

Like when I browse a website using SSL from my laptop that is connected to my router using WPA2. My router talks to my ISP using IPsec. Is that more secure or do these types of encryption have ...
6
votes
1answer
11k views

Difference between IPSEC SA and CHILD SA

Let us consider two network entities. Linux1 (eth0)=============IPSEC=============Linux2(eth0) 192.168.1.1 192.168.1.2 The IPSEC Tunnel is V4 ...
6
votes
1answer
4k views

Is L2TP as secure as IPSEC for VPNs?

Is it as secure to use L2TP for VPN access, rather than IPSEC? Am I introducing any risks by using L2TP?
6
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1answer
2k views

In IPSec what is the definition & purpose of SAD and SPD?

What is a Security Application Database & Security Policy Database? What is their role in processing models for OUTBOUND and INBOUND packets?
6
votes
2answers
7k views

How do I make or get computer certificates to use with IPSEC user authentication on Windows?

I am having trouble and need some direction using computer certificates with Windows 7 firewall IP Security rules, using certificates only for user authentication. I can get everything to work ...
6
votes
1answer
489 views

IPSec Host-to-Host VPN (RedHat) needs IP Forwarding?

We would like to build a Host-to-Host IPSec VPN (both RedHat Linux). Is it really mandatory to activate IP Forwarding which is by default deactivated because of our security policy (/etc/sysctl.conf ...
5
votes
2answers
13k views

How to detect Network Address Translation (NAT)?

How can I detect if NAT is used in network or not? I know if you have a private address and you are able to connect to a public network or the Internet, then there must be NAT. But how can I detect ...
5
votes
3answers
1k views

Books on Cryptography, with a focus on application to Network Security?

Looking for some nice text books in the field of network security as part of my course. Our course covers mainly tls, ssl, pgp, smime, vpn, md5, hmac ....
5
votes
1answer
33k views

Understanding the details of SPI in IKE and IPsec

I'm currently learning IKE and IPsec for an exam. I have a lot of information on how Security Parameter Indexes (SPI) are used in both protocols, but I'm having some problems figuring out the ...
5
votes
4answers
5k views

Encryption of headers in IPsec tunnel mode

I am learning about IPsec's transport and tunnel modes. I understand that transport mode encrypts only the payload of an IP packet and is used for communication between two entities that both ...
5
votes
1answer
4k views

How vulnerable is IPSec HMAC-SHA1

There are a few references out there that say HMAC-SHA2 must be used over HMAC-SHA1. If I am using an IPsec link with HMAC-SHA1, how vulnerable is it to being intercepted and cracked?
5
votes
3answers
1k views

Is there a reason to use both SSL & IPSec together?

As I understand, IPSec protects packets at IP layer and SSL/TLS at transport layer? Is there a scenario in which we might want to use both?
5
votes
2answers
3k views

IPsec - when to use AH only?

As far as I know, AH only covers integrity and authentication. So, suppose that an intermediate router receives the packet with AH and not ESP. Then, can't the router open its content (<- and that'...
5
votes
1answer
2k views

IPSec Domain Isolation with Windows Server

I'm looking for a good way to secure my servers, I have a set of dedicated servers that are not in my office but hosted by an external provider. ALL the servers have only one public (WAN) IP. I don't ...
5
votes
1answer
361 views

Does IPSec authenticate identity?

I know that SSL/TLS authenticates the identity of a server (and/or client) by presenting a certificate which the client sends to a CA to check the validity. This happens before the SSL/TLS connection ...
5
votes
1answer
2k views

Does using NAT-T for L2TP / IPsec VPN pose a realistic security risk?

I'm working on upgrading an old Windows RAS server that hosts PPTP VPN. I want to move to a L2TP/IPsec VPN. Due to the firewall appliance we use, the VPN server has to be behind a NAT. This means ...
5
votes
2answers
1k views

What are the risks associated with relying on IPSec IP Filtering?

When using Windows IPSec for IP filtering whenever a filter is added you need to have a "mirror" rule (by checking the "Mirrored. Match packets..." tickbox). Because IPSec Filtering is not stateful, ...
5
votes
2answers
2k views

IPsec on multicast

I am trying to implement IPSec for multicast communication, I tried strongSwan for setting up IPSec for unicast but it doesn't support any standard for multicast ipsec as listed here https://wiki....
5
votes
0answers
933 views

SSL vs IPsec what's the difference [duplicate]

Possible Duplicate: What is the difference in security between a VPN- and a SSL-connection? Which is more secure? And offer better access control?
4
votes
3answers
335 views

How can an outsider tap into communications between two physical sites?

When referring to 'Sites' - I am not talking about a website, but of a physical place where a company resides. Today, to secure communications between two sites - Let's say between an office in London,...
4
votes
2answers
1k views

Why do we need IPSec when we can encrypt data at Application layer?

We can Process encryption of data at application layer according to given key. So why do we need to use IPSec for security ? Lets say I want to send message to other machine over internet. Which one ...
4
votes
1answer
4k views

what is a security association and how does it relate to ipsec?

I am learning IPSec. My class notes define a security association as a one way relationship between sender and receiver that (1) affords security for traffic flow and (2) is identified by the ...
4
votes
2answers
106 views

IPSEC connection attempt to rogue server — is my PSK compromised?

I am setting up an IPSec connection between two sites using Ubiquiti EdgeOS-based equipment. Using a DDNS service (a static IP is unavailable from the ISP), they can be found at east.example.net and ...
4
votes
4answers
503 views

How can a network be secured against attacks coming from the inside?

(updated to (hopefully) be less broad) No matter how well one secures a network there's always the chance of an attacker gaining access. In a shared home + home office network (eg. for a remote ...
4
votes
3answers
32k views

authenticity, confidentiality & integrity - general questions

I am pretty new when it comes to information security. And before I move on with more specific things I wanted to ask if I understood the three main parts of IPsec correctly: authenticity, ...
4
votes
6answers
26k views

Why Use IPSEC AH vs ESP?

I am refreshing my understanding of IPSEC. IPSec is an IETF defined set of security services that use open standards to provide data confidentiality, integrity, and authentication between peers. ...
4
votes
1answer
448 views

IPsec: Is AH in tunnel mode secure?

I have a site-to-site IPsec VPN which was performing poorly (10 -20% upload/download speeds as a percentage of available WAN circuit bandwidth) when using ESP in tunnel mode with DES encryption and ...
4
votes
1answer
961 views

What does OAKLEY stand for?

IPsec uses ISAKMP + OAKLEY + SKEME right? This is strange but even after checking the RFC of OAKLEY, i couldnt find what it basically stands for? Can someone please point me to the right direction or ...