Es geht in eine weitere Runde bei den VPNs von und zur FRITZ!Box. Nach den unglücklichen Änderungen in Version 06.20 hat AVM wieder ein paar Phase 2 Proposals hinzugenommen, die komplett ohne Kompression laufen. Somit ist es wieder möglich, die FRITZ!Box im Aggressive Mode VPN-Verbindungen zu diversen Firewalls aufbauen zu lassen. Komisch nur, dass noch nicht alles ganz wie erwartet funktioniert. Hier kommen meine Testergebnisse.
Continue reading FRITZ!OS ab 06.23: IPsec P2 Proposals erweitert
Similar to my test with Diffie-Hellman group 14 shown here I tested a VPN connection with elliptic curve Diffie-Hellman groups 19 and 20. The considerations why to use these DH groups are listed in the just mentioned post – mainly because of the higher security level they offer. I tested the site-to-site IPsec connections with a Juniper ScreenOS firewall and a Fortinet FortiGate firewall. (Currently, neither Palo Alto Networks nor Cisco ASA support these groups.)
Continue reading Site-to-Site VPNs with Diffie-Hellman Groups 19 & 20 (Elliptic Curve)
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.
Continue reading IPsec Site-to-Site VPN FortiGate <-> Cisco ASA
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.
Continue reading IPsec Site-to-Site VPN FortiGate <-> Cisco Router
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.
Continue reading IPsec Site-to-Site VPN FortiGate <-> Juniper SSG
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.
Continue reading IPsec Site-to-Site VPN Palo Alto <-> FortiGate
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.
Continue reading Grep Commands for Cisco ASA Syslog Messages
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.)
Continue reading IPsec Site-to-Site VPN Juniper ScreenOS <-> Cisco Router w/ VTI
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.
Continue reading IPsec Site-to-Site VPN Palo Alto <-> Cisco Router w/ VTI
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.
Continue reading IPsec Site-to-Site VPN Cisco Router <-> AVM FRITZ!Box
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.)
Continue reading IPsec Site-to-Site VPN Juniper ScreenOS <-> Cisco Router
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.)
Continue reading IPsec Site-to-Site VPN Palo Alto <-> Cisco Router
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 misleading 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.
Continue reading Site-to-Site VPNs with Diffie-Hellman Group 14
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.