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what are the implications of two VLANs?

In addition to your existing VLAN2018:NYM1 a second one was assigned at
New-York data-center (VLAN2067:NYM1). VLAN contains 56 IP addresses,
starting with the
Now you can use both VLAN2018 and VLAN2067 IP ranges for launching
instances. Please, refer to our wiki page on how to launch instance,
assigning an exact IP to it
Note, that there is no need to restart or move your existing instances,
if you are not going to re-assign IPs to them. However, you can bundle
your existing instance for launching it next with another IP. To do that
use 'manage-instance bundle' command. Please,refer to aforesaid man page
for details.

ACL refers to a list IP addresses, both origin and destination, and ports where traffic is permitted to pass. The *router* does this? Access control lists can generally be configured to control both inbound and outbound traffic, and in this context they are similar to firewalls. How are they different from firewalls, is at all? Is the ACL just the "firewall settings"?
Link to How to Request Firewall Changes

VLAN is a list of IP addresses that you control. This means that you can control access to those IP addresses. You can assign these addresses as you like. Traffic within a VLAN is encrypted (question) How?

Relevant tickets: #4128 /#4625/#3952

1. What do you want customers to know about AppNexus VLANs and VLAN requests and migrations?
2. How does it work to have a VLAN in NY and a VLAN in LA?
3. What do you do when you want a bigger VLAN?
4. What's the migration process?
5. Will migrating be available through the API in the future?
6. Can you add IPs to a VLAN or connect two VLANs?6. Multinetting?? Does it turn two VLANs into one?
7. OK so looks like multinetting is nixed by Peak. So how to two VLANs interact? How does that work? And what's the optimal solution here?
8. VPNs??? What are they exactly. Customer VPN question and answer:

What is the capacity of our VPN hardware?
Currently there is no customer-allocated VPN hardware. If you need VPN capabilities, please let us know and we may be able to provide them to you for a fee.

Stateful vs. non stateful inspection.

These questions are also answered on the wiki FAQ but may be helpful here.

1. Why do you use ACLs instead of a stateful firewall?

Stateful inspection is most useful for protecting outbound traffic, but with hosting, the servers tend to receive traffic instead of initiate it. Also, because we are dealing with an unknown amount of traffic, the ability to scale is very important. Stateful inspection is an expensive task for a device to perform and therefore subject to strict capacity limitations (we're talking sub Gigabit for most firewalls). On the other hand, Cisco routers perform ACL packet filtering at line rate with absolutely no performance hit. So, while stateful inspection is appropriate for small, stable amounts of outbound traffic or for protecting niche pieces of the network, (like e-commerce databases), ACLs are more scalable and efficient for protecting inbound traffic to servers. If a customer still desires a stateful firewall, we can add it for a fee.

2. What are the security implementations at each relevant layer of the OSI Reference Model?

  • Layer 1 - (Physical Layer) All your network gear and servers are protected in secure, locked colocation facilities.
  • Layer 2 - (Data Link Layer) Extensive use of VLANs provides segregation of each customer's traffic from AppNexus traffic and other customers' traffic.
  • Layer 3 - (Network Layer) Bi-directional ACLs are applied on every routing interface with a Default Deny policy, meaning only explicitly permitted traffic is allowed to pass.
  • Layer 4 - (Transport Layer) The use of TCP-based protocols provides connection reliability and allows for session protection via ACLs and host firewalling.
  • Layer 7 - (Application Layer) There is extensive use of encryption (SSH, SSL-VPN) throughout the network.

3. How do you detect, prevent, and manage DDoS attacks and application-level attacks?

Preemptive protection against DDoS attacks is difficult, because we have no way of knowing when, where, or what type to expect. Also, please note that AppNexus does not manage nor monitor the customer's applications (even their OS). That said, in the event of an attack the use of Cisco ACLs allows us to apply deny statements for the source of the attack without affecting performance of the rest of the network. Also, we highly recommend that our customers utilize the F5 server load balancing technology for front-ending their web applications, as the F5s provide built-in DDoS protection when it performs full-proxy session offload.

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