Category Archives Networking

I've been thinking about where I wanted to direct my focus within the networking industry of late.   I've always been interested in security and privacy, so studying the Cisco Security pathway made sense. Working in a NOC type environment has a use for security, but it doesn't come up all that much past access lists, securing the router, VPN's and…

Today I came across an interesting case when troubleshooting an access list. The device was a Cisco 1921 which had an access list defined to permit certain hosts' incoming traffic from the outside to an FTP server. What was interesting is that the access list only contained permit statements (apart from the implicit deny at the end), but traffic from…

Below is a short sequence describing the steps an ASA takes when authenticating VPN users. First, the user initiates a connection to the ASA. The ASA is configured to authenticate that user with the Microsoft Active Directory (AD)/LDAP server. The ASA connects to the LDAP server with the credentials configured on the ASA (ASAusername in this case), and looks up the user provided username.…

SNMP is an application layer protcol which provides the ability for an agent and a manager to process important information. An agent is on the device you wish to retrieve information from and write it to a database. The database the agent writes to is called the Management Information Base (MIB). If an agent is set to RW, the management…