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 ...

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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 ...
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is IPSEC Authentication between local domain hosts a part of normal behaviour in a Windows network?

I am seeing lot of IPSEC Authentication messages in eventlogs of Windows domain hosts. I was wondering if this - setting up IPSEC connections between domain workstations is a part of normal Windows ...
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1answer
145 views

PFS incentive during IKE Phase 2

I'm trying to see the actual point in implementing Perfect Forward Secrecy during Internet Key Exchange Phase 2, if it had already been used during Phase 1. Quoting the IKEv2 RFC: RFC 5596 ...
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1answer
34 views

IPSec sequence number

I was going through a study of IPsec and I found that there are redundant sequence numbers: one in the AH or ESP header, and the other is in the TCP header for a communication. Is it not an ...
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1answer
112 views

How should IPSec be configured to provide a protection at least as good as my current Stunnel configuration?

In private network (as in using a private IP address space) at a cloud provider, other customers have access to the same private network. I have secured the communication between many hosts and ...
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1answer
34 views

Is it possible to use AH in transport mode on an IPSec channel with mediation?

I understand that it's not possible to have Autentication Header with a regular NAT, because it messes with the IP header protected by AH. How about proxies? Do they change anything in the packet? ...
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1answer
64 views

IPSec optional advanced questions [homework] AH/ESP and Tunnel/Transport modes

I have 2 questions regarding IPSec. This is the last 2 optional questions of my homework: Scenario when combining AH and ESP can be needed? Scenario when combining Tunnel and Transport modes can be ...
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1answer
105 views

Skype Audio / Video Session over VPN?

Basically I'm wondering if a Skype video session along with audio could be logged (or recorded) over a virtual private network? I know whoever hosts the VPN server can log which websites you visit (or ...
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2answers
114 views

Is QuickVPN Secure

Does QuickVPN create a secure tunnel or how does it work to provide encryption and security? When I did a see my IP it was using the remote locations IP and not my office network's IP so does that ...
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1answer
72 views

NAT traversal for IPsec AH protocol

Wherever I looked I only saw the description of NAT traversal for ESP protocol (for example: http://pic.dhe.ibm.com/infocenter/iseries/v6r1m0/index.jsp?topic=/rzaja/rzajaudpencap.htm) It's looks that ...
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221 views

How does IPSec protect against IP spoofing?

IPsec is a security mechanism that provides peer-entity authentication, data-origin authentication, data integrity, and optionally data confidentiality. It relies on extensions to the standard IP ...
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2answers
630 views

How to detect NAT - network address translation?

How to detect if NAT is used in network or not ? I know if you have private address and you are able to connect public network or internet then there must be NAT. But How can I detect that NAT is ...
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1answer
104 views

how can I secure my static ip router?

hi I have a static ip and someone is hacking my computer trought it I tried to format my computer and making a clean install but he keeps penetrating it this time i tried to install the AV before ...
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1answer
88 views

Using secp256k1 and ECDSA with IKE

I just tried using an IKE daemon and EC certificates. I used the secp256k1 curve for key generation. The daemon claims signature scheme ECDSA-256 not supported by private key Now I am wondering ...
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2answers
680 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 ...
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2answers
1k 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 ...
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1answer
138 views

Is it necessary to use PEAP for L2TP/IPsec?

This is a sister question of Is EAP-MSCHAP v2 secure?. Based on my understanding, IPsec should have authenticated the server (we're using PKI) and secured the rest of the protocols before the user ...
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1answer
216 views

How to authenticate to racoon with a certificate chain if only the root CA is known

I'm trying to setup IPsec using x509 certificates on Linux. I'm using racoon for that task. I've come to the point where the authentication works fine if I keep every link of the certificate chain on ...
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2answers
1k views

IPsec using pre-shared keys

I am trying to understand why do we really use those pre-shared keys when creating a IPSec tunnel. From all the reading that I have done the DH group creates the keys that are used to do the actual ...
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2answers
431 views

Strongswan crypto

How does StrongSwan enable different crypto libraries?
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1answer
85 views

Where else is IPSec used, besides with VPNs? [closed]

IPSec is most commonly used to secure VPN traffic. Where else is this protocol suite used? What else can it be used for?
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4answers
2k 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 ...
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1answer
102 views

IPSec, hubs, crypto maps

I thought hubs were layer 1 devices, and so would have no active role in IPSec. I am reading to understand crypto maps, Dynamic crypto map policies are used in site-to-site VPNs when an unknown ...
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3answers
497 views

Filtering In Iran

Since many of you already know the Iranian government aggressively uses internet censorship to block sites such as facebook, flicker, bbc, etc. The Iranian people use various methods to bypass ...
2
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1answer
129 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 ...
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2answers
639 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 ...
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1answer
564 views

IPSec AH + ESP used together

When ESP and AH are used together (ESP transport, AH transport) on the same packet does ESP encrypt the AH's hash, or is the hash left in the clear? If the hash isn't encrypted, there are obviously ...
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1answer
498 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 ...
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1answer
213 views

Normalizing Windows Advanced Firewall rules

How can I best normalize our Windows Advanced Firewall rules while implementing network segmentation? I want them to be as clear and concise as possible for audit purposes. What few examples I've seen ...
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3answers
183 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 ...
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2answers
405 views

What software can I used to edit and replay packets? [closed]

From the Wikipedia article on anti-replay: The main goal of anti-replay is to avoid hackers injecting or making changes in packets that travel from a source to a destination. Is this commonly ...
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4answers
833 views

IPSec VPNs and symmetric keys

When dealing with IPSec based VPNs, I understand that there is a slight "problem" with symmetric key exchange. Obviously, you can't send the keys over the VPN, since they are used to guarantee the ...
5
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1answer
631 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 ...
4
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2answers
559 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 ...
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1answer
307 views

IPSec Tunnel Creation process

The IPSec tunnel creation process involves 2 steps: The ISAKMP Phase The IPSec Phase What is the reasoning behind having the two phases? From what i see, the first phase is already encrypted using ...
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2answers
95 views

Using External Certificates on a network that doesn't permit outbound HTTP/S access

Some highly secure networks and DMZs prevent all communication to outside hosts. This can cause issues with validating externally signed data I can guess that issues with signature validation occur ...
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1answer
200 views

network improvements over ipsec

I have a specific environment in which TCP is not optimal due to its general assumptions, and thus needs to be improved. This small improvement has been done successfully. It operates at various ...
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2answers
2k 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 ...
2
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1answer
303 views

Does iOS use built-in certificates to authenticate peers when using ipsec VPNs?

Suppose I am setting up an IPsec VPN for Apple iOS clients with the requirement that the iOS clients need to know that the server is legitimate and vice-versa. I create a root CA and issue a ...
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2answers
1k views

L2TP/IPsec shared secret: Can it be public?

My university provides a VPN service to gain access to internal services to all members. They are apparently using an L2TP/IPsec solution by Cisco. I'm able to connect just fine, but I'm a bit ...
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1answer
1k 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 ...
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3answers
145 views

What organisation(s) is able to recommend a baseline technology set for safe, secure, web browsing?

This is a high level question regarding some recent posts about enhancing web browser security from an end-user perspective. What business/organisation(s) would have: Sufficient technical skill ...
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3answers
736 views

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

I am looking at different VPN protocols. [1] L2TP does not provide encryption so require IPSec to encrypt the data [2] IPSec tunnel provide encryption to the tunnel What is the difference in terms ...
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6answers
1k 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 ...
5
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2answers
549 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
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3answers
632 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 ....
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1answer
4k views

strongswan setup for ipsec environment

I have created two virtualbox ubuntu clones for the purpose of setting up a test strongswan ipsec network; I'm trying to follow this guide. The virtualbox machines are on a bridged adapter and i ...
5
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0answers
815 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?
8
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1answer
1k views

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

As the title says really, 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 it's own IP ...
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1answer
2k 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?