Following is a step-by-step tutorial for a site-to-site VPN between a Fortinet FortiGate and a Cisco ASA firewall. I am showing the screenshots of the GUIs in order to configure the VPN, as well as some CLI show commands.
This blog post shows how to configure a site-to-site IPsec VPN between a FortiGate firewall and a Cisco router. The FortiGate is configured via the GUI – the router via the CLI. I am showing the screenshots/listings as well as a few troubleshooting commands.
Here comes the step-by-step guide for building a site-to-site VPN between a FortiGate and a ScreenOS firewall. Not much to say. I am publishing several screenshots and CLI listings of both firewalls, along with an overview of my laboratory.
This is a small tutorial for configuring a site-to-site IPsec VPN between a Palo Alto and a FortiGate firewall. I am publishing step-by-step screenshots for both firewalls as well as a few troubleshooting CLI commands.
Pre-shared keys (PSK) are the most common authentication method for site-to-site IPsec VPN tunnels. So what’s to say about the security of PSKs? What is its role for the network security? How complex should PSKs be? Should they be stored additionally? What happens if an attacker catches my PSKs?
I am listing my best practice steps for generating PSKs.
In a basic environment with a Cisco ASA firewall I am logging everything to a syslog-ng server. As there aren’t any reporting tools installed, I am using grep to filter the huge amount of syslog messages in order to get the information I want to know. In this blog post I list a few greps for getting the interesting data.
And finally: A route-based VPN between a Juniper ScreenOS SSG firewall and a Cisco router with a virtual tunnel interface (VTI). Both sides with tunnel interfaces and IPv4 addresses. Both sides with a real routing entry in the routing table. Great. ;)
(The VPN between those two parties without a tunnel interface on the Cisco router is documented here. However, use the route-based VPN where you can. It is easier and more flexible. Routing decisions based on the routing table. This is how it should be.)
One more VPN article. Even one more between a Palo Alto firewall and a Cisco router. But this time I am using a virtual tunnel interface (VTI) on the Cisco router which makes the whole VPN set a “route-based VPN”. That is: Both devices decide their traffic flow merely based on the routing table and not on access-list entries. In my opinion, this is the best way to build VPNs, because there is a single instance (the routing table) on which a network admin must rely on in order to investigate the traffic flow.
Note that I also wrote a blog post about the “policy-based VPN” between a Cisco router and the Palo Alto firewall. This here is mostly the same on the Palo Alto side while some other commands are issued on the Cisco router.
Der Titel sagt eigentlich schon alles: Es geht um das Herstellen eines S2S-Tunnels zwischen einem Cisco Router (statische IPv4) und einer FRITZ!Box (dynamische IP). Ich liste nachfolgend alle Befehle für den IOS Router sowie die Konfigurationsdatei für die FRITZ!Box auf. Für eine etwas detaillierte Beschreibung des VPNs für die FRITZ!Box verweise ich auf diesen Artikel von mir, bei dem ich zwar ein VPN zu einem anderen Produkt hergestellt habe, aber etwas mehr auf die Schritte der Konfiguration eingegangen bin.
Similar to all my other site-to-site VPN articles, here are the configurations for a VPN tunnel between a Juniper ScreenOS SSG firewall and a Cisco IOS router. Due to the VPN Monitor of the SSG firewall, the tunnel is established directly after the configuration and stays active all the time without the need of “real” traffic.
I am using the policy-based VPN solution on the Cisco router and not the virtual tunnel interface (VTI) approach. That is: No route is needed on the router while the Proxy IDs must be set on the Juniper firewall. (However, I also documented the route-based VPN solution between a ScreenOS firewall and a Cisco router here.)
This time I configured a static S2S VPN between a Palo Alto firewall and a Cisco IOS router. Here comes the tutorial:
I am not using a virtual interface (VTI) on the Cisco router in this scenario, but the classical policy-based VPN solution. That is, no route entry is needed on the Cisco machine. However, the Palo Alto implements all VPNs with tunnel interfaces. Hence, a route to the tunnel and Proxy IDs must be configured. (I also wrote a guide for a route-based VPN between a Cisco router and a Palo Alto firewall here.)
When talking about VPNs it is almost always clear that they are encrypted. However, it is not so clear on which security level a VPN is established. Since the Perfect Forward Secrecy (PFS) values of “DH group 5” etc. do not clearly specify the “bits of security”, it is a misleadingly assumption that the security is 256 bits due to the symmetric AES-256 cipher. It is not! Diffie-Hellman group 5 has only about 89 bits of security…
Therefore, common firewalls implement DH group 14 which has a least a security level of approximately 103 bits. I tested such a site-to-site VPN tunnel between a Palo Alto and a Juniper ScreenOS firewall which worked without any problems.
I tested the Palo Alto GlobalProtect app on my iPhone, but also the native IPsec Cisco VPN-Client on iOS which connects to the GlobalProtect Gateway on a Palo Alto firewall, too. Since this variant needs no further licenses from Palo Alto, it is a cheap alternative for a basic VPN connection.
Though not that much exciting, there are a few differences in the logs on the firewall which I will show here on the basis of a few screenshots.
This is a tutorial on how to configure the GlobalProtect Gateway on a Palo Alto firewall in order to connect to it from a Linux computer with vpnc.
Short version: Enable IPsec and X-Auth on the Gateway and define a Group Name and Group Password. With this two values (and the gateway address), add a new VPN profile within vpnc on the Linux machine. Login with the already existing credentials.
Long version with screenshots comes here:
During the last few months the concept of Perfect Forward Secrecy (PFS) was presented on many newspapers and guidelines. This concept is related to the session key generation for SSL/TLS as well as for IPsec tunnels. And even though many of these articles describe the benefit of PFS, I was still missing a picture that shows the main difference between the classical key exchange via RSA and the exchange via Diffie-Hellman with PFS. So, here comes my poster. ;)