Cisco ACI - Port Tracking

One of the techniques to speed up convergence in case of internal fabric connectivity failures, "port-tracking" feature addresses an outage where a leaf node loses connectivity to "all" the spine nodes in the Cisco ACI fabric.
In such a scenario, the hosts that are connected to such a leaf in active-standby setup are usually not aware of such an outage and continue to send traffic to the now isolated leaf.
This is where the port-tracking feature brings down all the host facing ports of the isolated leaf node.
For the servers that are dual homed to different leafs, this action would ensure that the uplink to the isolated leaf is not considered for forwarding the traffic.

The changes can be made as below:

System >> System Settings >> Port Tracking

Comments

Checkpoint - Exporting Objects in CSV format

Be it a Network Operations Manager, Security Architect or a Security Auditor, the people up the hierarchy always harangue the Security Engineers to compile the list of firewall objects or rules or policies or the traffic statistics and so on.. This can turn out to be quite hectic especially if there are no built in features to systematically provide the output in a "layman-readable" format. Come, Checkpoint's "Object Explorer..." which not only provides the output in the "layman-readable" format, but also provides in-built filtering mechanisms, thereby ensuring that the Security Engineer doesn't have to rely on Google for building his scarce Microsoft Excel data filtering skills. The following screenshots will show how easy it is, with Checkpoint R80.10 to generate the firewall configuration inventory. On the SmartConsole Unified Portal, navigate to Menu >> Open Object Explorer... Select the Categories you wish to see in your output: Click o

MITRE ATT&CK - Kerberos Vulnerabilities and Security

From the previous post, the summary of Kerberos authentication process is as below: For the initial authentication, the user’s client machine sends a request to the KDC Authentication Service (AS) . The request includes details like the user’s username, and the date and time. All information except the username is encrypted using the hash of the user’s password. The KDC AS uses the username to look up its copy of the user’s password hash and uses it to decrypt the rest of the request. If the decryption is successful, that means the client used the correct password hash and the user has successfully authenticated. Once the user is authenticated, the KDC AS sends the user’s client a ticket granting ticket (TGT) . The TGT includes a unique session key and a timestamp that specifies how long that session is valid (normally 8 or 10 hours). Importantly, before sending the TGT, the KDC encrypts it using the password hash for a special account, the KRBTGT account. That password hash is s

Tejas Jain - GCP Constraints & Random Facts

1. Google Cloud Interconnect Security Cloud Interconnect does not encrypt the connection between your on-premises network and Google's network. Cloud VPN cannot be used with Dedicated Interconnect For additional security, use application-level encryption or your own VPN 2. While using Cloud CDN, the default time-to-live (TTL) for content caching is 3600 seconds = 60 mins 3. Cloud NAT sends only the translation logs and error logs to Cloud Logging service. 4. GCP Dedicated Interconnect - On Premises network device requirements: 10-Gbps circuits, single mode fiber or 100-Gbps circuits, single mode fiber IPv4 link local addressing LACP, even if you are using single circuit EBGP-4 with multi-hop 802.1Q VLANs 5. While using Cloud VPN, the recommended MTU to be configured on the peer VPN gateway = 1460 bytes 6. Each instance must have at least one network interface. The maximum number of network instances per instance is 8, depending on the instance's machine

Tejas Jain

Search This Blog