Senario:
There are two servers running on different VPCs. Both servers are publically available.
Server-one(e.g. Public IP:13.126.233.125) is hosting one file on 8000 port and port 8000 inbound is open on all firewall installed on the server and security group.
Server-two wants to get that file with "wget command". Port 80 outbound Server-two is open. I tried to do "wget http://13.126.233.125:8000/file.txt", it shows connection refused. I had to open port 8000 in outbound of Server-two to make this work.
As per my logic, this should have worked without adding 8000 in out-bound list. Server-one is hosting on 8000, It's not compulsory for server-two to start the connection from 8000 port. server-two can use any ephemeral ports or port 80 as this is http connection.
Please explain why it's required to open out-bound port 8000 on server-two.
HTTP is a protocol that sits on top of TCP. Using port 80 is a convention and not a requirement. You can run HTTP (and HTTPS) on any port you want that is available. The way that TCP works, is that a process will open a TCP port (say 8000) and then "listen" on that port for connection attempts from other systems (local or remote). If you try to connect using port 80 on a system listening on port 8000, you will either connect to the wrong service or get connection refused. Only after the connection is accepted does ephemeral ports come into action.
If server A is running a service listening on port 8000, then server B needs to connect to server A using port 8000. This means that server B needs port 8000 open outbound in order to connect to port 8000.
In normal usage, you set (restrict) the inbound ports in a security group and allow ALL outbound ports. Only restrict outbound ports if you understand how TCP works and know exactly what you are doing and why. Otherwise leave all outbound ports open.
There are a few reasons to control outbound ports. For example, to prevent an instance from performing updates, to prevent an instance from communicating if was breached, etc. If you are controlling this level of communications, then you also need to understand how NACLs work and how to use each one.
AWS has some pretty good documentation that explains how security groups and NACLs work and how to use them.
Outbound firewalls are used to limit the connections to external services from within the network. That is why by default all outbound connections are enabled and inbound connections are disabled.
In this case, setting an outbound firewall on server 2 prohibits server 2 from making connections to port 8000 (and all others, except 80) of server 1. It is regardless of the port from which the connection is initiated.
Related
i want to open up port 8080 to https connections.
but the port number is locked at 443 for all https connections. http is also locked at 80 and ssh at 22.
the reason i want to do this is because the image below shows a dockerized django project working on my machine
but the image below shows the docker container not connecting in my ec2 container
how can i open up port 8080 to connect to my ec2 container from my browser.
update
evidence below of of it not connecting still
Port numbers are just conventions (or 'standards') used for particular protocols. You can certainly use different port numbers for your services.
If you have a web server running on 8080 that is expecting HTTPS connections, you would need to:
Select "Custom TCP" and port 8080 in the Security Group, then add the appropriate IP address range (such as 0.0.0.0/0 for the whole Internet, or perhaps just your specific IP address) -- you can ignore the 'protocol' field since is simply listing the 'standard' uses for each port number
Point your web browser to port 8080, such as:
https://ec2-54-91-36-1.compute-1.amazonaws.com:8080
I have Elasticseasrch and Kibana installed on EC2 instance where I am able to access Elasticsearch using on this url http://public-ip/9200. But I am unable to access Kibana using http://public-ip/5601.
I have configured kibana.yml and added certain fields.
server.port: 5601
server.host: 0.0.0.0
elasticsearch.url: 0.0.0.0:9200
On doing wget http://localhost:5601 I am getting below output:
--2022-06-10 11:23:37-- http://localhost:5601/
Resolving localhost (localhost)... 127.0.0.1
Connecting to localhost (localhost)|127.0.0.1|:5601... connected.
HTTP request sent, awaiting response... 200 OK
Length: 83731 (82K) [text/html]
Saving to: ‘index.html’
What am I doing wrong?
Server Host set to 0.0.0.0 means it should be accessible from outside localhost but double check that the listener is actually listening for external connections on that port using netstat -nltpu. The server is also accessible on it's public IP on port 9200 so try the following:
EC2 Security Group should inbound TCP traffic on that port 5601 from your IP address.
Network ACLs should allow inbound/outbound TCP traffic on port 5601.
OS firewall ( e.g. ufw or firewalld ) should allow traffic on that port. You can run iptables -L -nxv to check the firewall rules.
Try connecting to that port from a different EC2 instance in the same VPC. It is possible that what ever internet connection you are using may have a firewall blocking connections on that port. This is common with corporate firewalls.
If these fail, next you want to check if the packets are reaching your EC2 instance so you can run a packet capture on that port using tcpdump -ni any port 5601 and check if you have any packets coming in/out on that port.
if you don't see any packets on tcpdump, use VPC Flow Logs to see if packets are coming in/out that port.
Considering the kibana port (5601 ) is open via security groups
I could able to resolve the issue by updating config server.host:localhost to server.host:0.0.0.0
and elasticsearch.hosts: ["http://localhost:9200"] (in my case kibana and ES both are running on the same machine) in kibana.yml
https://discuss.elastic.co/t/kibana-url-gives-connection-refused-from-outside-machine/122067/8
I already did the configuration as the documentation sends and the door does not open.
Firewall Rules Config
Netstat on server
Nmap
Google Firewall rules are for just to allow traffic to the instance. In your case, seems you have to open the port 8080 from the server level.
I am using tcp load balancer in google cloud platform, How do i forward the the frontend configurations
<static-ip>:8000 and <static-ip>:80
to the 8000 port of a backend instance group ?
The temporary solution i have used is by logging into each machines in the instance group and used ip-tables to forward the incomming traffic in port 80 to port 8000. But this is not a feasible solution if the number of instances are more.
Port forwarding cannot be implemented in google cloud's tcp loadbalancer, but available in HTTP and HTTPS load balancers. The port forwarding should be done through ip-tables in the machines.
I'm trying to connect to my Hansoft server on my AWS server that is running Windows Server.
I've tried opening all inbound traffic to test, but that hasn't worked. I'm able to ping the server so it's there.
Hansoft servers use default port 50256.
What else could I try?
Launch-wizard-1 security group settings below.
Inbound Security rules:
All Traffic, All protocols, All port range, Source 0.0.0.0/0
RDP, TCP Protocol, Port range 3389, Source 0.0.0.0/0
All ICMP, All protocols, Port range N/A, Source 0.0.0.0/0
Outbound Security rules:
All Traffic, All protocols, All port range, Source 0.0.0.0/0
Try the following:
Are you sure 100% the service is running?
While logged into the instance, can you 'telnet localhost 50256' and get a connection? Have you tested it locally and confirms it works?
Disable your local firewall and anti-virus.
Have you checked the local Windows Firewall on that server? That will block you in some configurations, so you need to check that. You may need a new inbound rule there.