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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45 views

Performance comparison between AES256 GCM vs AES 256 SHA 256

I understand GCM Crypto uses ESP Encryption only for ESP and Authentication algorithm. whereas AES 256 SHA256 uses AES for ESP Encrypt and SHA256 for Auth algorithm. Could someone help clarify the ...
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What is the real risk of clicking a link? [closed]

If I were to click a link on any of my devices, be it over text message, email, or from a webpage, and enter no information/actions with the target page. What is the worst that could happen?
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Why IKEv2 uses UDP and not TCP? [migrated]

As per the IKEv2 RFC 7296, it is a reliable protocol. Since UDP is a datagram (unreliable) protocol, IKE includes in its definition recovery from transmission errors, including packet loss, packet ...
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How does IKEv2 work on Android without raw sockets

I was exploring the IKEv2 StrongSwan client implementation for Android. What I fail to understand is that Android and Java do not support raw sockets, whilst the IKEv2/IPSec works below the transport ...
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45 views

Is PFS recommended by the NCSC in the PRIME profile for IPsec

Guidance on the PRIME profile for IPsec (https://www.ncsc.gov.uk/guidance/using-ipsec-protect-data) does not explicitly mention the use of PFS. Is there a recommendation for its use in the Prime ...
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98 views

StrongSwan, IPsec remote certs and cert_policy

I'm looking for a way to limit the certs that my IPsec can accept. I'm using StrongSwan (swanctl version 5.7), I want to accept only certs coming from a remote with a name of yoji.*.example.com I ...
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1answer
116 views

CA certificate and Local certificate

There is something which is bothering me when i think about the CA cert and Local cert. Below are my queries which pertains to juniper but may be generic as well. 1) "request security pki ca-...
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1answer
54 views

What are the changes in PKI when i move from TLS protocol to IPSec Protocol?

Currently i am using TLS protocol for a secure communication between my server and client. I use PKI for key/certificate Management. If i want to switch to IPsec for secure communication, how will the ...
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Which VPN offers more security conceptually, SSL VPN or L2TP/IPSEC?

Aside from possible implementation bugs, which VPN concept aims to offer more protection by design? SSL VPN (implementation example - OpenVPN) L2TP/IPSEC (implementation example - Strong Swan) After ...
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“ip xfrm state deleteall” vs “ip xfrm state flush” commands

Please explain the purpose of the following commands and differences between them. ip xfrm state deleteall ip xfrm state flush According to the man page : ip xfrm state deleteall - delete all ...
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1answer
87 views

IKEv2 Using Different PSKs

We're setting up some new tunnels and have been told to use IKEv2. I understand that IKEv2 allows different authentication methods, e.g. one side using PSK and the other using a certificate. We don't ...
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how ipsec differentiates between re-transmitted tcp segment and malicious one?

How Ipsec protocol differentiates between re-transmitted TCP segment (which is re-transmitted because the sender didnt get the ACK last time) and a malicious one?
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71 views

authby=secret serve as alternative to AH in ipsec.conf

I have employed strongSwan U5.5.1 for installing an IPsec tunnel between two Debian hosts with a firewall in between. My ipsec.conf specifies authby=secret but not ah=. The firewall currently permits ...
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Could IPSec flows be decrypted using PSK [duplicate]

I created an IPSec tunnel between two VMs using StrongSwan. It relies on a Pre-Shared Key. I wonder, if this key is leaked, what could an attacker perform? Would he/she be able to decrypt previous ...
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1answer
85 views

IPsec installed algorithms

What happens if a laptop and a server don't have a encryption algorithm in common? Does IPSec abort the connection or does it always have default algorithms?
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Ipsec: Is it possible to use both pre-shared keys and pubkeys auth methods at the same time?

So if we have a server configuration with local auth pubkeys and remove psk and at the same time for a client(initiator) a local auth psk and remote pubkey. Something like this. Server - local { ...
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78 views

IP Encryptor and Firewall

Firewalls implement IPsec VPN and perform packet filtering. IP Encryptor, on the other hand implements IPsec VPN and achieve security goals (confidentiality, integrity and authentication). What are ...
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2answers
72 views

TCP Traffic, SSL or extra Tunnel

I have a situation where we (as a SaaS vendor) are migrating one of our clients away from their local premise to our public SaaS. However as a security concern they want to route all their TCP ...
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1answer
110 views

Is a security association (SA) implemented in ESP and AH protocols?

I'm reading about security associations. I've understood that a SA is a virtual connection between a client and a sever, in which all the security parameters, such as encryption algorithm, IP origin ...
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1answer
503 views

How hard is it to retrieve IKEv2 Server Certificate from the server?

I got access to a VPN via IPsec and IKEv2. The provider gave me a username, a shared secret and a server certificate. Since the certificate was self-signed, the manual came with specific instructions ...
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99 views

IPSec Sniff Traffic

I'm wondering if it is possible to Sniff IPSec connections. At the beginning of a connection, the two peers agree on a SA and exchange a PSK or Certificates. What I'm thinking about, is to ...
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Where would I go to use a reliably secure encrypted internet connection?

Lately, I’ve been paying $100 a month for Fios. I’m thinking of canceling this service because I rarely use my internet at home, since I’m at school most of the time and my college offers internet (...
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343 views

Maximum number of certificates generated by a CA

What is the maximum number of certificates that can be generated from a CA? The use case is a VPN using certificate authentication and I would like to know what is the theoretical number of unique ...
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1answer
175 views

IKE Phase 1 /w PSK resource?

I can't seem to find a sufficiently detailed resource that describes the IKE phase 1 PSK identity authentication process. They seem to focus on differences between aggressive and main mode while ...
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1answer
72 views

IPsec down with unusual SNMP traffic [closed]

Time to time IPSec tunnel status become down, with unusual SNMP Traffic. when I disable and enable port manually, it become normal. I am using 200E fortigate firewall. Have you any idea or previous ...
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1answer
84 views

IPsec with PSK: Can PSK be used for passive eavesdroping?

I use a PSK to connect to an IPsec VPN. Let's say an attacker can gain access to my PSK. He can then impersonate me, that much is clear. But would she also be able to decrypt intercepted traffic? ...
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118 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 ...
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1answer
5k views

Which PFS Group is recommended for IPSec configuration?

I can't find much information on PFS (Perfect Forward Secrecy) Groups so I'm unsure what to suggest for a secure IPSec configuration. Any suggestions on PFS groups that aren't recommended? What is ...
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251 views

What alternatives to IPSec for diversifyed redundancy?

I need to provide redundancy to an IPSec link between two premises. I would like to have no single point of failure and to diversify technologies. What could I use please? Are the following leads ...
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611 views

Please explain the vulnerability for the pre-shared Key for IKEv1 brute force IPSec

After the vulnerability was released for IPSec IKEv1 PSKs, our organization decided to increase the size and complexity of the PSK. However, upon releasing the new PSK we had a few issues: ...
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691 views

Why doesn't IKEv2 use L2TP?

My guess is that with IPSec/IKEv1, since it doesn't support NAT, you either have to manually configure routes from your machine, or use a layer 2 tunnel (such as l2tp) to talk with devices on the ...
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Do I need Gateway Firewall for IoT network? [closed]

Do I need a gateway firewall to prevent attacks like DoS, if my IoT network can only talk to cloud using IPsec? Even if there is need that can be implemented at cloud. Is there any need for it to ...
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1answer
584 views

How to use IPsec Transport mode between two gateways

I have read many comparisons of IPsec Transport vs. Tunnel mode, and there is a clear understanding that when two gateways are exchanging routed traffic they should use Tunnel mode. In other words, ...
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How does Cisco Anyconnect VPN work?

I am looking for a deep down technical explanation of how it works. My understanding is its an SSL VPN and works as follows: - Anyconnect creates a TLS session to the configured remote servers, ...
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1answer
421 views

Differentiating between IKEv2 and OpenVPN Traffic

There is a WiFi network that I regularly use, and it seems to be blocking all VPN traffic other than IKEv2. I tested this by downloading many of the free/freemium VPN apps from the Google Play Store ...
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1answer
307 views

Is IP address whitelisting useful if the IP address is not “secret”?

I'm working on an application that will have access to API keys supplied by our users. The application makes API calls on behalf of our users. The API we're using allows users to whitelist IP ...
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Disable SSLv3 in IPSec CentosOS

I have been told to shut down support to SSLV3 - TLS 1.0 - TLS 1.1 to all encrypted communications towards external web services. Now, I have an IPSec/CentOS gateway in front of my Data Center.How ...
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1answer
540 views

IPsec Transport Mode NAT Traversal Security Risks

The strongSwan FAQ states: NAT-Traversal with IPsec transport mode has some inherent security risks. What kind of security risks is the documentation referring to? (links to other resources are ...
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303 views

Why rekey long-lived connections?

Why is rekeying after a certain period of time, or after a certain volume of data transfer, often implemented in modern secure transport protocols such as ESP or TLS? What are the security risks of ...
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2answers
390 views

What is meant by IPSec is “transparent”

While reading a guide on IPSec, i came across this sentence: IPSec is transparent to the user and the applications. Can someone please tell me what is meant by being transparent from security view ...
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2k views

IP Security (IPsec) vs Public Key Infrastructure (PKI)

I've found the following question on the internet and don't think the answer is right. Which of the following does IPsec use? A) SSL B) AES C) DES D) PKI The given answer is D, PKI ...
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IPSec and traffic mirroring [closed]

I have a VoIP server on which several SIP clients are connected to through IPSec tunnels. This is kind of an automated attendant so I both have RTP and SIP signalling flows. I need to be able to ...
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2k views

CHAP vs MS-CHAPv2

I'm setting up an L2TP/IPSec VPN, and I can't find any information about this. MS-CHAPv2 has a known vulnerability that makes cracking it relatively easy. Is CHAP more secure? Does MS-CHAPv2's vuln ...
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How often ciphers are used through an IPSEC session

I’m wondering how often a terminal needs to perform a cryptographic hash (ex: SHA) throughout the lifetime of an IPSEC session where both ends are authenticated using certificates. From what I can ...
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142 views

Is ESP without AH considered noncompliant with FIPS 140-2?

I have a CentOS 7.4 box running kernel 3.10 that has the fips=1 parameter defined in the kernel grub statement. If I attempt to add an IPSEC SA with the following command it fails: ip xfrm state ...
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1answer
715 views

Question about ipsec prevent SYN flooding attack

how IPSec prevents SYN flooding attacks Like if A is sending packets to B using IPsec. Suppose B’s TCP ack gets lost, and A’s TCP retransmits the packet since it assumes the packet was lost. Will B’s ...
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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-...
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239 views

What is the Identification Payload of RFC2407 used for in IPsec?

RFC2407 outlines the Identification Payload in section 4.6.2, which appears in the fifth and sixth packets of the Main Mode's SA negotiation when using IKEv1. What is this information used for? From ...
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562 views

How does IKE with PSK really work and how secure is it?

There is many articles that describe some exploitation techniques on a VPN with IPSec - IKE-PSK. However, I can't understand how the flaws may exist. Thus, I have some question relating to that: 1) ...
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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 ...