Configure Your Firewall for SNMP
KB ID 0001034 Problem Had a requirement to let SNMP traffic though a firewall this week, I have a client that has both SolarWinds and SCOM, and they need to monitor the external Citrix ADC load balancers. For SNMP we simply need UDP ports 161 and 162 (See below) but SolarWinds maintains ‘ping’ connectivity to the monitored assets, so ICMP also needs to be open. Inbound Ports Outbound Ports Solution As my ‘weapon of...
Cisco ASA – ‘access-group’ Warning
KB ID 0001035 Problem I’ve been writing Cisco ASA walkthroughs for years, and littered all over PeteNetLive you will see me warning readers every time I use access-group commands. So I’ve finally got round to putting this article up so I can reference it in future. What is an Access-Group command? You use an access-group command to apply an access-list to an interface, in a particular direction (in or out). Although I...
Cisco ASA – Policy NAT
KB ID 0001042 Problem I’ve been working on a large firewall deployment for a client, each of their DMZ’s have both a production and a management network. nothing particularly strange about that, but each of their DMZ’s has its own firewalled management network and it’s routable from the LAN. So If I’m an admin and I want to talk to a Linux appliance in their DMZ via its management interface, my traffic...
Cisco ASA – ‘Prove it’s Not The Firewall!’
KB ID 0001049 Problem Yeah, it’s funny because it’s true! The article title might not sound like the most professional approach, but when the ‘Well it’s not working now’ finger gets pointed at the ‘firewall guy/girl’, they need to ascertain two things; 1. Is the problem actually the firewall, if not then help the frustrated party track down the actual problem. 2. If your problem IS the...
Cisco ASA – View The Contents of an Object and Object-Group
KB ID 0001043 Problem My colleague loves the ASDM, I put up with it and prefer command line. We were troubleshooting a problem the other day and he said, there this is why I prefer the ASDM, just ‘hover’ over an object-group and it will show you the contents of it. Now if (like my test firewall above) you only have a few hosts, then I don’t see the point, but if you have a very complicated config with hundreds of...