You have a load balancer configured for VPC, and all back-end Amazon EC2 instances are in service. However,
your web browser times out when connecting to the load balancer’s DNS name. Which options are probable
causes of this behavior? Choose 2 answers
A.
The load balancer was not configured to use a public subnet with an Internet gateway configured
B.
The Amazon EC2 instances do not have a dynamically allocated private IP address
C.
The security groups or network ACLs are not property configured for web traffic.
D.
The load balancer is not configured in a private subnet with a NAT instance.
E.
The VPC does not have a VGW configured.
A and C
I am confused.Somewhere else I have got answer as A and C. Please let me know which one is correct with proper document link
I think B and C, but I am not 100% sure
(But I think C for sure can cause such behavior)
I was wrong,
B is wrong (ELB don`t need EC2 to have public IP to send traffic to it),
A and C should be right answers
You are absolutely right.
Correct answer is AB
I choose AC.
B is wrong: EC2 always had private IP attached to it.
I choose A&C.
B is wrong because Private IP addresses are not dynamic but persistent.
Regards
AC
A & E are pretty much means the same thing. Not sure why picked A and not E.
Both will result in ELB not reachable as the VPC used is not connected to internet (Not public).
Any reasoning that help me understand the difference?
There is no such thing as VGW. Hence E is not correct answer.
Right answer is A & C.
VGW is virtual private gateway used for VPN configuration.
AC
CE
C – port 80 may not be open
E – As this is a VPC, you would like need VGW configured to connect to a private subnet.
For A, I don’t recall in any of the LAB for Load Balancer, we need to attach a Internet GW to a public subnet in order for it to work. We just need to apply the LB in the VPC and it will be assigned a DNS link automatically.
When you create an ELB/ALB you must specify the subnets it will be in. So for web facing ELB’s you’d assign them to one or more public subnets (per AZ) and of course a subnet is public if i’s default route is to an IGW
http://docs.aws.amazon.com/elasticloadbalancing/latest/classic/elb-manage-subnets.html
So A and C
A C as Paul explained
AC
A,C
A and C are the right answers..