Problem: Troubleshooting vpn slowness and packet retransmits could be a puzzling task, especially when it’s over an IPsec tunnel. Last week I had the opportunity to troubleshoot a problem with slow website loading times on a webserver across the link….
Today I ran into a weird scenario where a Linux system’s NIC would set itself to 100Mb half duplex regardless whether the device and NIC was manually configured to operate at full duplex. After strolling through Cisco’s website Troubleshooting Cisco…
Firstly, Nat 0 and static can be used to achieve the same result of bypassing NAT, at least logically 🙂 However both are fundamentally different. Take a look at the following example: nat (inside) 0 192.168.1.1 255.255.255.255 and static (inside,dmz)…
The inside interface of the PIX (also applies to ASA) cannot be accessed from the outside or from the other side of the VPN tunnel unless the management-access is configured. Once management-access is enabled, Telnet, SSH, or HTTP access must…
When setting up a Cisco ASA failover pair, try to follow the following rules & tips: Do not use a crossover Ethernet cable or a fiber-optic patch cable to directly connect the two failover LAN interfaces if the firewalls are…
If you are having issues routing your traffic within the inside interface, or hair-pining your traffic, chances are you need to enable the “same-security-traffic permit intra-interface” command. Take a look at the picture below which explains this problem: Basically when…
After analyzing the situation I have identified several key problems. 1. System Availability – Systems fail frequently due to hardware failures, DoS, and application failures. 2. Collocation is far and administration requires frequent visits 3. Mini tower servers consume space…
Today I was assigned a task to find out and explain a certain network anomaly we are experiencing in our network. The mission started out to be a bandwidth monitoring task against a specific router. This router however was owned…
I think I should be stepping up my security practices. Here’s an article that I came across summarized all the things one should know about Layer 2 security practices on Cisco switches. http://www.networkworld.com/community/node/30682
Today, I got a chance to setup some bandwidth limiting on our Cisco ASA Firewall. The goal was to choke the speed of traffic going to our backup server to 250Mb/s. As our backup traffic goes through a firewall here’s…