Few days ago I configured firewall on EC2 in AWS. But, the problem was when I configure firewall in EC2, that server went down. Then when I remove this firewall, then the server went up again. but after restarting the server, it was down. then when I disabled firewall from the server it gone up, then remains ok also after restarting further. My question is should we avoid firewall installing on aws EC2?, as the firewall is automatically configured by aws instance. but won't it increase the security by configuring firewall. Did, I do something wrong like double layer protection by installing firewall?
Enabling the Firewall/Security Groups/ does not DOWN the server, it is still up and running but maybe inaccessible to you, as you might have locked yourself from it.
This is exactly the reason why the EC2 Security Groups are there, so you can block access to specific ports and allow access only from specific ports for management, and/or open public access to Web services for example.. if you are building a webserver.
Firewalls can be dangerous if you do not know what you are doing.
If you locked yourself out, then Yes you did something wrong. If you first allow your IP in the firewall, then you will still be able to manage or access it, once the Firewall is up.
Related
I am trying to set up my JMeter master/slave set up on AWS EC2 instances using windows. Out of the box integration didn't work (connection refused errors) and after some investigation I got to know that RMI communication only works if the machines are on same subnet (is this true?). I found this great article and I tried to follow it as is on windows (tried running ssh port forward tunneling via cygwin) but not have any luck. So I was hoping if someone already done this with Windows and can share their experience.
Out of the box integration didn't work (connection refused errors) and
after some investigation I got to know that RMI communication only
works if the machines are on same subnet (is this true?)
It is not necessary. Even if the machines are in a different subnet and addressable via the network, RMI should work. Here make sure the Security Groups and NACLs are properly set so that both EC2 instances can communicate with each other via the network.
You can check whether you can ping(For this you need to enable ICMP in your Security Groups and also make sure other needed ports are opened for RMI) from one EC2 instance to another. If the servers can communicate with each other, then you need to troubleshoot internal firewall configuration in windows EC2 instances.
We have used https://testable.io/ AMI's from the marketplace. It takes care of all configuration and just needs to worry only about testing and the results.
https://aws.amazon.com/marketplace/pp/B073JNTVKP
All our endpoints are secured to certain IP-ranges from testable.io. If you have internal, still you need to setup those security settings.
Hope it helps.
After installing Tigase on an AWS EC2 instance I keep getting the error message 'connection refused' when I try to connect to it using an xmpp client.
The instance is attached to a security group with rules to allow traffic to the necessary ports (tigase needs 5223 primarily and some others for more exotic features). I've also tried it with rules allowing all traffic to all ports from all sources but I still get the same message.
I've also checked iptables because I noticed some people needed to configure those as well in specific cases, I made sure it allows all connections but still I can't connect to Tigase.
Yes Tigase is running, there are no relevant errors in the Tigase logs
SSH (port 22) and HTTP (port 80) work fine
Enabling ICMP (ping) on all ports works fine
I've tried several xmpp clients, same problem
I've deleted and recreated instances several times
Re-installed Tigase on fresh instances several times with various configuration options
Tried using domain name associated with Elastic IP, normal IP and tried public DNS directly.
Configured the DNS in the way necessary for Tigase as described here
I've looked everywhere and have not been able to find anything to fix this. Networking isn't my main area of expertise and I'd really appreciate any advice.
Wow, in case anyone runs into the same problem in the future, turns out that this was related to the AMI. I was using an Amazon Linux AMI and switched to Ubuntu Server 14.04 LTS. I wish I tried this sooner but I didn't really consider this a possible solution earlier. Apparently Amazon Linux doesn't play well with Tigase.
I had a running instance, and then I became unable to connect to it via http(80) and ssh(22). I tried to reboot the instance, but nothing went up. This has happened to me twice in the past month.
Why does it happen? Can I do anything to fix and/or prevent it from happening?
If I launch a new instance in same region, and it works.
Things to check when trying to connect to an Amazon EC2 instance:
Security Group: Make sure the security group allows inbound access on the desired ports (eg 80, 22) for the appropriate IP address range (eg 0.0.0.0/0). This solves the majority of problems.
Public IP Address: Check that you're using the correct Public IP address for the instance. If the instance is stopped and started, it might receive a new Public IP address (depending on how it has been configured).
VPC Configuration: Accessing an EC2 instance that is launched inside a Virtual Private Cloud (VPC) requires:
An Internet Gateway
A routing table connecting the subnet to the Internet Gateway
NACLs (Network ACLS) that permit through-traffic
If you are able to launch and connect to another instance in the same subnet, then the VPC configuration would appear to be correct.
The other thing to check would be the actual configuration of the operating system on the instance itself. Some software may be affecting the configuration so that the web server / ssh daemon is not working correctly. Of course, that is hard to determine without connecting to the instance.
If you are launching from a standard Amazon Linux AMI, ssh would work correctly anytime. The web server (port 80) would require installation and configuration of software on the instance, which is your responsibility to maintain.
I have a domain www.rentcars.sg which is pointed to the right DNS server and verified by someone else and is working correctly: https://forums.aws.amazon.com/message.jspa?messageID=362885#362885
However, even though I setuped the domain correctly on the server with IIS, it's not working correctly.
Can anyone point me to the right direction? Is there any additional setup I need to make to get it working?
Server IP : 23.23.129.247
Using the internal IP, it works but not with the server ip with port/url.
I am not sure if I understand your problem, but my approach would be:
Allocating EC2 Elastic IP Address.
Associating such an address with your running EC2 instance.
Pointing your domain name to this IP address.
Adding inbound TCP rule for all IP sources (0.0.0.0/0) in Security Group settings belonging to your EC2 instance.
Keep in mind that windows instances in AWS come with the software (windows) firewall enabled by default. Make sure that you have the correct firewall policies in place in the software firewall as well as the security group.
I have a free Amazon EC2 instance. And I installed Apache web server on it. I have the DNS record for my domain point to the ip for the EC2 instance. I can not access to my website. Then I looked up and allow the http inbound. But I still failed to access my web? What might be the reason. Anybody gives me a clue?
Go to the AWS management console and look at the Security Group the instance is in. Then make sure you have the port open that you are trying to connect to (most likely 80). To open it to the world set the ip range to 0.0.0.0/0 and to open it to a specific ip (like only your house) set it to xxx.xxx.xxx.xxx/32.
That is almost always the reason people have problems connecting when they are new to AWS. I wrote this post, which should help get you setup.