Tag: asa
Cisco ASA: multiple context and capture
Packet captures are very useful for troubleshooting purposes. The Cisco ASA supports packet captures even in multiple context mode. I normally configure packet captures on CLI level. This can be done by configuring an access-list to match the specific traffic you would like to capture. Add the access-list and the specific interface in a capture command. … Read More
Configuration Example, Firewalling
Cisco ASA – Reset TCP connection
“Normal” TCP applications use a three-way handshake to establish a session. After data has been send the session is closed. Some legacy applications don’t always close a TCP session. They keep the session open, even when the session is idle for a long time (+ 2 hours). When the session is idle and a client … Read More
Cisco ASA – Full recovery
While trying to perform a password recovery on a Cisco ASA, I noticed that the password recovery feature was disabled on the appliance. Without the password recovery feature enabled, you can recover the Cisco ASA, but the file system will be wiped completely. During the boot of the Cisco ASA you need to press ESC … Read More
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
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
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