Juniper SSG to Cisco ASA VPN with overlapping subnets
I needed to configure a site-to-site VPN connection between a Juniper SSG firewall and a Cisco ASA firewall. The configuration of a VPN connection is very straightforward, but this time the networks behind the firewalls are overlapping. I have configured the Cisco ASA multiple times in such scenario, but the configuration of the Juniper SSG … Read More
OpenSSL for testing TLS
I was looking for a way to test the TLS configuration of a secure mail server and stumbled across a website called “OpenSSL Command-Line HOWTO”. This websites explains how to test a TLS connection using OpenSSL. The s_client and s_server options provide a way to launch SSL-enabled command-line clients and servers. There are other examples … Read More
Configuration Example, Firewalling, Routing
NBAR and smart filtering
NBAR (Network Based Application Recognition) is a cool Cisco tool to identify and classify content flowing through a router. You can identify applications as mission critical, business-related, non-critical or unwanted. Once these mission critical applications are classified they can be guaranteed a minimum amount of bandwidth, policy routed, and marked for preferential treatment. Non-critical applications … Read More
Cisco ASA remote management via VPN
By default, remote access VPN users aren’t able to manage a Cisco ASA firewall on the inside interface using any kind of management protocol (SSH, telnet, HTTPS). You can enable remote management by specifying the management-access interface. You can specify the interface via the CLI or via the Cisco Adaptive Security Device Manager (ASDM). Both … Read More
XS4ALL, Cisco 877 and IPv6
A while ago my ISP XS4ALL started with the distribution of IPv6 prefixes to their customers. So as a network engineer I wanted to have my own /48 prefix. Sadly I didn’t had time to start testing at the beginning of the IPv6 “launch”. Last week I found some time to start my testing. I … Read More
Cisco ASA NPE image
I got complains from a customer who wasn’t able to configure 3DES or AES encryption for a VPN tunnel. Sounds familiar with a problem I had a couple of weeks ago. So I gave the customer the advice to upgrade and activate the VPN-3DES-AES feature. He tried but that didn’t solve this problem. I remotely … Read More