Demonstrating traffic flow through a firewall
by James Denton
Learning OpenStack Networking (Neutron) - Second Edition
- Learning OpenStack Networking (Neutron) Second Edition
- Table of Contents
- Learning OpenStack Networking (Neutron) Second Edition
- Credits
- About the Author
- About the Reviewers
- www.PacktPub.com
- Preface
- 1. Preparing the Network for OpenStack
- 2. Installing OpenStack
- System requirements
- Initial network configuration
- Initial steps
- Installing OpenStack
- Summary
- 3. Installing Neutron
- 4. Building a Virtual Switching Infrastructure
- Virtual network devices
- Network types supported by Neutron
- Choosing a plugin and driver
- Visualizing traffic flow when using LinuxBridge
- Visualizing the traffic flow when using Open vSwitch
- Configuring the ML2 networking plugin
- Configuring the LinuxBridge driver and agent
- Configuring the Open vSwitch driver and agent
- Summary
- 5. Creating Networks with Neutron
- Network management
- Neutron ports
- Attaching instances to networks
- Exploring how instances get their addresses
- Exploring how instances retrieve their metadata
- Summary
- 6. Managing Security Groups
- Security groups in OpenStack
- An introduction to iptables
- Working with security groups
- Managing security groups in the CLI
- Creating security groups in the CLI
- Deleting security groups in the CLI
- Listing security groups in the CLI
- Showing the details of a security group in the CLI
- Updating security groups in the CLI
- Creating security group rules in the CLI
- Deleting security group rules in the CLI
- Listing security group rules in the CLI
- Showing the details of a security group rule in the CLI
- Applying security groups to instances and ports in the CLI
- Removing security groups from instances and ports in the CLI
- Managing security groups in the CLI
- Implementing security group rules
- Working with security groups in the dashboard
- Disabling port security
- Summary
- 7. Creating Standalone Routers with Neutron
- Routing traffic in a cloud
- Installing and configuring the Neutron L3 agent
- Router management in the CLI
- Creating routers in the CLI
- Working with router interfaces in the CLI
- Listing the interfaces attached to routers
- Deleting internal interfaces
- Clearing the gateway interface
- Listing routers in the CLI
- Displaying router attributes in the CLI
- Updating router attributes in the CLI
- Deleting routers in the CLI
- Network address translation
- Floating IP management
- Demonstrating traffic flow from an instance to the Internet
- Setting the foundation
- Creating an external provider network
- Creating a Neutron router
- Attaching the router to the external network
- Testing gateway connectivity
- Creating an internal network
- Attaching the router to the internal network
- Creating instances
- Verifying instance connectivity
- Observing default NAT behavior
- Assigning floating IPs
- Reassigning floating IPs
- Router management in the dashboard
- Summary
- 8. Router Redundancy Using VRRP
- 9. Distributed Virtual Routers
- Distributing routers across the cloud
- Installing and configuring Neutron components
- Routing east-west traffic between instances
- Centralized SNAT
- Floating IPs through distributed virtual routers
- Summary
- 10. Load Balancing Traffic to Instances
- Fundamentals of load balancing
- Integrating load balancers into the network
- Installing LBaaS
- Load balancer management in the CLI
- Building a load balancer
- Load balancer management in the dashboard
- Summary
- 11. Firewall as a Service
- Enabling FWaaS
- Firewall Management in the CLI
- Managing firewall rules
- Managing firewall policies
- Creating a firewall policy in the CLI
- Deleting a firewall policy in the CLI
- Listing firewall policies in the CLI
- Showing the details of a firewall policy in the CLI
- Updating a firewall policy in the CLI
- Inserting rules into firewall policies in the CLI
- Removing rules from firewall policies in the CLI
- Managing firewalls
- Creating a firewall rule
- Creating a firewall policy
- Creating a firewall
- Demonstrating traffic flow through a firewall
- Summary
- 12. Virtual Private Network as a Service
- A. Additional Neutron Commands
- B. Virtualizing the Environment
- Index
To see how firewall policies are applied to a Neutron router, take note of the following firewall rule, which allows HTTP traffic from any source to any destination on TCP port 80:
Figure 11.10
The firewall rule was applied to the policy named MyFirewallPolicy as shown in the following screenshot:
Figure 11.11
As the final step, the policy is associated with a firewall, MyFirewall, as shown in the following screenshot:
Figure 11.12
Once a firewall is created, the rules within the firewall policy are implemented on the associated router. Running iptables -L -t filter or iptables-save within a router namespace reveals the iptables rules that are implemented by the L3 agent. For readability, only the filter table is shown in the following screenshot:
Figure 11.13
As with security groups, the FORWARD chain is used as the traffic is forwarded through the namespace rather than directed at it:
-A FORWARD -j neutron-filter-top -A FORWARD -j neutron-l3-agent-FORWARD
A neutron-filter-top chain does not exist, so the traffic moves to the neutron-l3-agent-FORWARD chain, as shown in the following screenshot:
Figure 11.14
The first rule matches all traffic exiting any qr-* interface attached to the router and sends it to the neutron-l3-agent-iv4a4040d8b chain:
Figure 11.15
The packets that are invalid are dropped, while the established connections are accepted without further processing. New connections destined to any destination address on port 80 are allowed.
The next rule in the neutron-l3-agent-FORWARD chain matches all traffic entering any qr-* interface attached to the router and sends it to the neutron-l3-agent-ov4a4040d8b chain:
Figure 11.16
As with the previous chain, the packets that are invalid are dropped, while the established connections are accepted without further processing. New connections destined to any outside network on port 80 are allowed.
The traffic that does not match rules in either of the mentioned chains is dropped by the neutron-l3-agent-fwaas-defau chain via the following command:
-A neutron-l3-agent-fwaas-defau -j DROP
Unlike security group rules, there is no way to differentiate between the directions of the traffic when we create firewall rules with the FWaaS API. By default, firewall rules are applied to both incoming and outgoing traffic in an identical manner. Work is underway in the FWaaS project to solve this issue and others in future OpenStack releases.
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