Cisco Simple GRE Tunnels (With IPSEC)
KB ID 0000951 Problem I’ve spent years setting up VPN tunnels between firewalls. The only time I’ve ever dealt with GRE is for letting VPN client software though firewalls. GRE’s job is to ‘encapsulate’ other protocols and transport those protocols inside a virtual point to point link. Below is the topology, I’m going to use. The tunnel will run form Router R1 to Router R3, once complete I should be...
Cisco – Configuring Dynamic Multipoint Virtual Private Networks DMVPN
KB ID 0000954 Problem A while back I uploaded a run through on how to deploy GRE tunnels and protect those tunnels with IPsec. That point-to-point GRE tunnel is a good solution, but if you have a lot of sites it’s not a solution that scales very well. Yes you can have 2147483647 tunnel interfaces, but good luck manually configuring all those tunnels and even if you did, if you want each of your remote sites to talk to each other...
Implementing GDOI into DMVPN
KB ID 0000956 Problem Just recently I covered DMVPN, which is a great scalable system for adding new sites to your network infrastructure and have them join an existing VPN solution without the need to add extra config at the ‘hub’ site. One of the advantages of DMVPN is it maintains VPN connections from your ‘Spoke’ sites back to the ‘Hub’ site, but if a spoke site needs to speak to another spoke...
Cisco ASA Site to Site VPN’sSite to Site ISAKMP VPN (Main Mode)
KB ID 0000213 Problem As with most things, before you have a hope of fixing something, you will stand a better chance if you know how it works in the first place. Below is a quick run though of what’s happening with your site to site VPN’s and how they work. For the entire process we will have two Cisco ASA 5500 firewalls and a site to site VPN. Solution What’s an Initiator and a Responder? 1. Our Laptop 192.168.1.50...
ASA 5500 AnyConnect – Change Preferred Encryption Cipher Order
KB ID 0001058 Problem A few days ago I wrote about disabling SSL v3.0 to force your clients to connect with the more secure TLS v1.0. But what if your AnyConnect clients chose to connect with a weaker encryption cipher? The ciphers your firewall offer (by default) will vary depending on what OS your ASA is running. Solution 1. To see what your cipher you are connected with look on the statistics tab, below we are connecting with the...