Can't access another AWS ec2 instance (in the same subnet) - amazon-web-services

I'm setting up an AWS VPC with both private and public subnets. In public subnets, I created 2 instances: one as bastion host and one as a web server. For the web server, I only want to make port 80 open to public, but SSH access needs to done through the bastion host.
I created 2 paris of SSH keys. One is dedicated for public access to bastion host from external. Another is for private SSH access from bastion host to the web server (and all other instances that will be created in the private subnets).
At the moment, I can SSH to bastion host as expected. But from bastion host, I can't SSH into the web server, althoug I have the right inbound securiy rules. In order to find the issue, I did some more tests. First, I expanded the inbound rule on the web server to allow public SSH access. Once I do so, I can SSH into the web server from external. Second, I add rules for ICMP traffic both from bastion host only and from public (0.0.0.0/0). But again, I can ping from external, but not from bastion host.
Below is the webserver (IP: 191.100.0.56) inbound and outbound rules. Note that IP 191.100.0.162 is the bastion host IP.
[WebServer Inbound rules]
Ports Protocol Source
22 tcp 191.100.0.160/32, 0.0.0.0/0
[WebServer Outbound rules]
Ports Protocol Source
All All 0.0.0.0/0
The subnet ACL is default which is Allow ALL for both inbound and outbound.
100 ALL Traffic ALL ALL 0.0.0.0/0 ALLOW
* ALL Traffic ALL ALL 0.0.0.0/0 DENY
I'm wondering where could be the problem? This is a bit strange to me. Why I can access (SSH or ping) from public, but not from the bastion host?

Related

GCP - Unable to access instance via SSH

I am unable to access my VM instance on Google Cloud Platform and I have the issue isolated I believe to the VPC firewall rules. If I allow all ingress traffic (0.0.0.0/0) then obviously I can access the instance via SSH, however if I replace 0.0.0.0/0 with my exact IPv4 address, I receive the following:
No ingress firewall rule allowing SSH found.
If the project uses the default ingress firewall rule for SSH,
connections to all VMs are allowed on TCP port 22. If the VPC network
that the VM’s network interface is in has a custom firewall rule, make
sure that the custom firewall rule allows ingress traffic on the VM’s
SSH TCP port (usually, this is TCP port 22).
I get my IP address from browsing (whatsmyipaddress on Google) as well as the following below in terminal, so I know I have my IPv4 public IP address correct:
dig +short myip.opendns.com #resolver1.opendns.com
I am unsure as to why when I use my public IP address as 'allow ingress' to match on all ports with my exact IP, I am not allowed in, but a simple switch to 0.0.0.0/0 life is great. Any help would be appreciated.
Seems as though when you connect by SSH using the browser, the IP address that instantiates the in-browser SSH connection is a Google IP, which seems to be the reason I am unable to connect, given the firewall rules I had set in place.

Route only api traffic to other AWS EC2 instance

I am new to networking. And I am trying to route only traffic from one VM traffic to another VM. Therefore, I have done this.
I have two AWS EC2 instances as:
Application Server
Database Server
And they have their own security groups and I have allowed all traffic is permissible. Now I want to Database_server accepts only Application_server traffic not all public traffic. Database_server is MySQL which is running on 3306 port.
Suppose:
Application_server Public IP: 14.233.245.51
Database_server Public IP: 15.233.245.51
So I have allowed on port 3306 like this 14.233.245.51/32 for only Database_server but it did not work. It was before this 0.0.0.0/0 and ::/0.
How can I solve this?
First, the application server should communicate with the database server via private IP address. This will keep all traffic within the VPC and will enable security groups to work correctly.
Second, configure the security groups:
App-SG should be associated with the application server and permit incoming traffic on the appropriate ports for the application (eg 80, 443)
DB-SG should be associated with the database server and permit incoming traffic on port 3306 from App-SG
That is, DG-SG permits inbound traffic from App-SG by referring to the ID of App-SG. There is no need to specify an IP address. The security groups will automatically recognize the traffic and permit the App server to send traffic to the DB server. Return traffic will also be permitted because security groups are stateful.
You MUST communicate with the database server via private IP address for this to work.

EC2 - Make Windows instance accessible from anywhere (XAMPP)

I've launched an EC2 instance on AWS, no after setting up XAMPP and uploading all my archives it's now time to make the site public.
Thing is that I've already tried to put all the firewall on windows allowing inbound and outbound connections to "allow" and then also on my AWS Security groups this:
Inbound:
HTTP TCP 80 0.0.0.0/0
HTTP TCP 80 ::/0
Custom TCP Rule TCP 0 - 8080 0.0.0.0/0
Custom TCP Rule TCP 0 - 8080 ::/0
Outbound:
All traffic All All 0.0.0.0/0
As i mentioned before, i allowed all inbound and outbound connections on the windows firewall of the instance.
What am i doing wrong and how can i fix this issue to make the server accessible from the IP that amazon assigned my instance?
Thanks.
Couple of things to check:
(Obvious One) Make sure the application is listening on port 80 / 8080 (You mentioned both ports in SGs. Not sure on which port your application is running)
If you are planning to access your application over the internet, make sure you have public IP assigned to your instance.
Check your NACLs if both inbound and outbound rules are added. If you are accessing the app from a specific VPC / OnPrem network, add it to NACLs. If you dont want to restrict your app and want to access over internet, make sure you have 0.0.0.0/0 is added in NACL inbound and outbound
If accessing the app over internet, you need to have Internet gateway assigned to your VPC.
Hope this helps troubleshooting your issue. Provide more details like, you instance is in public subnet or private subnet. Weather you are accessing app from within the VPC or over internet etc.

Cannot SSH to MY EC2 From any network

I Cannot SSH to MY EC2 From any network ( my home-network, my workplace, or my Linode box) or ping the EC2 instance. I have all the necessary ports open, inbound and outbound. My IP address is 54.89.239.56, And the instance is RUNNING What could this be.**
Inbound
SSH TCP 22 0.0.0.0/0
SSH TCP 22 ::/0
All ICMP - IPv4 All N/A 0.0.0.0/0
All ICMP - IPv4 All N/A ::/0
Outbound
All traffic All All 0.0.0.0/0
The standard things to always check when attempting to connect from the Internet to an EC2 instance are:
Internet Gateway attached to the VPC
You are referencing the instance via a Public IP Address
Instance was launched in a public subnet, which means that the subnet is associated to a Route Table that routes to the Internet Gateway
Security Group is permitting the inbound traffic from your IP Address and port (outbound traffic configuration is irrelevant because Security Groups are stateful)
Network ACL is not blocking the traffic (by default it permits all inbound and outbound traffic)
The instance is listening on the port (eg Linux SSH on port 22, Windows RDP on port 3389)
There are no host-based firewalls on the instance blocking traffic (eg Windows Firewall)

Accessing WebApplication exposed by EC2 instance in Private Subnet

We have a web-application page exposed at port 9090 on an EC2 instance that lives in the private subnet of our AWS setup.
We have a bastion host that is in the public subnet, and it can talk to the instance in the private subnet. We can also ssh to the instance thru the ssh tunnel of the bastion.
Is there a guide to setting up a proxy on this bastion host to access the webpage in the browser that is served on the http://PrivateSubnetEC2Isntance:9090/, by redirecting the traffic to/from http://PublicBastion:9090/?
I tried setting up a HAProxy (on bastion), but it doesn't seem to work: there are no errors in the HAproxy logs, but accessing the page http://PublicBastion:9090 just times-out.
Though this is not an answer, most likely it could be due to:
Security group rules: Did you open port 9090 for everyone in Bastion security group?
Is your HAProxy listening on 0.0.0.0 and not on 127.0.0.1?