I'm trying to have two process communicate through a socket connection. One of these is a python app, and the other is a php script.
I've created and tested the client/server combination on my home computer and it functions properly. However, when I deploy onto an EC2 instance (ubuntu 10.10 64bit ami + apache + php) I get an unable to connect to socket error (111 Connection Refused) from the php script. The python app is able to bind to the socket and listen to messages but the php script is unable to send messages.
I've opened the required ports in the amazon security group and I can connect to the port externally using telnet. However if I attempt to connect with telnet from within the server I get the same connection refused error.
How can I solve this issue?
Edit: Both processes are on the same instance
The issue had nothing to do with EC2 explicitly. I was not binding to localhost, but instead binding to my hostname. On a local network that was the same as my localhost ip, however on ec2 it was not. Switching to binding to localhost fixed the issue.
Related
There is a PostgreSQL server on a Windows computer that I need to access remotely. It's not on the local network. I'm trying to connect to it with pg_pconnect. I have an AMP stack with PHP 7.1.23 on my local Mac computer and I can connect to it just fine. (The connection works, I can make queries, etc.) When I upload the same script to a hosting provider (LAMP stack with PHP 7.1.22) the script does not work anymore.
Warning: pg_pconnect(): Unable to connect to PostgreSQL server: could not connect to server: Connection refused
Is the server running on host "x.x.x.x" and accepting
TCP/IP connections on port 5432? in /path/to/my-script on line 42
I would think that the SQL server does not allow remote connections if it didn't allow the connection from my computer either. But to that server both connections would be remote, right? So how can it allow one and not allow the other?
Turned out that the hosting provider had to whitelist the IP address first. That's why it didn't work.
I am trying to connect AWS RDS PostgreSql from PgAdmin 3. I followed the below link
http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_ConnectToPostgreSQLInstance.html
In Security Group, I also added PostgreSQL and All traffic as below
The "publicly accessible" flag was enabled (updated after Mark B's comment)
I got the error from PGAdmin3
Very appreciate for any suggestion
******UPDATE*******
I can connect pgAdminIII to AWS RDS successfully using home wifi, but cannot connect using office wifi.
My concern is:
Was the port 5432 blocked by office wifi?
How can I configure/update the port without impacting to current API?
Note: My current API is working well (CRUD)
Can you can test your connection to a DB instance using common Linux or Windows tools first?
From a Linux or Unix terminal, you can test the connection by typing the following (replace with the endpoint and with the port of your DB instance):
$nc -zv DB-instance-endpoint port
For example, the following shows a sample command and the return value:
$nc -zv postgresql1.c6c8mn7tsdgv0.us-west-2.rds.amazonaws.com 8299
Connection to postgresql1.c6c8mn7tsdgv0.us-west-2.rds.amazonaws.com
8299 port [tcp/vvr-data] succeeded!
Windows users can use Telnet to test the connection to a DB instance. Note that Telnet actions are not supported other than for testing the connection. If a connection is successful, the action returns no message. If a connection is not successful, you receive an error message such as the following:
C:>telnet sg-postgresql1.c6c8mntzhgv0.us-west-2.rds.amazonaws.com
8299
Connecting To sg-postgresql1.c6c8mntzhgv0.us-west-2.rds.amazonaws.com...Could not
open connection to the host, on port 819: Connect failed
If Telnet actions return success, then you are good to go.
If you are trying to access it from a network which is not listed for that port. you need to add inbound rules for those network IPs from AMAZON RDS system
You will also need to set Public accessibility true under Connect & security tab in RDS console.
Read this post.In your security group go to unbound rules and add my ip.
and make sure your database is public.
https://serverfault.com/questions/656079/unable-to-connect-to-public-postgresql-rds-instance
I am using postgres database which is accessed by jboss and tomcat server.
My server accidentally restarted and then postgres service was not showing in the services list.
When I tried to open postgres local host server using pgadminIII it showed following error:
Server doesn't listen
The server doesn't accept connections: the connection library reports
could not connect to server: Connection refused (0x0000274D/10061) Is the server running on host "localhost" (::1) and accepting TCP/IP connections on port 5432? could not connect to server: Connection refused (0x0000274D/10061) Is the server running on host "localhost" (127.0.0.1) and accepting TCP/IP connections on port 5432?
If you encounter this message, please check if the server you're trying to contact is actually running PostgreSQL on the given port. Test if you have network connectivity from your client to the server host using ping or equivalent tools. Is your network / VPN / SSH tunnel / firewall configured correctly?
For security reasons, PostgreSQL does not listen on all available IP addresses on the server machine initially. In order to access the server over the network, you need to enable listening on the address first.
For PostgreSQL servers starting with version 8.0, this is controlled using the "listen_addresses" parameter in the postgresql.conf file. Here, you can enter a list of IP addresses the server should listen on, or simply use '*' to listen on all available IP addresses. For earlier servers (Version 7.3 or 7.4), you'll need to set the "tcpip_socket" parameter to 'true'.
You can use the postgresql.conf editor that is built into pgAdmin III to edit the postgresql.conf configuration file. After changing this file, you need to restart the server process to make the setting effective.
If you double-checked your configuration but still get this error message, it's still unlikely that you encounter a fatal PostgreSQL misbehaviour. You probably have some low level network connectivity problems (e.g. firewall configuration). Please check this thoroughly before reporting a bug to the PostgreSQL community.
Does this problem arise due to accessing same DB by two different servers?
My server accidentally restarted and then postgres service was not
showing in the services list.
You can't connect because it's not running. You can have as many clients connecting to a PostgreSQL server as your hardware can support - there is no problem with that.
Restart your PostgreSQL service. If it won't, check the logs for why. If you don't know where your PostgreSQL logs are now is a good time to find out. I can't tell you how to restart the service because you haven't said what OS you are running or how you installed PG. Check your documentation.
I have started an ubuntu instance on AWS EC2
e.g. [ec2-user#ip-XXX-XX-XX-XX ~]$
Inside this instance, I am running a socket program for sending the data to my local system.
The program is running properly, but not able to connect to my local IP.
I am trying to ping my local system also from AWS ec2 user, but it is also not working.But I am able to ping google(8.8.8.8).
e.g. [ec2-user#ip-xxx-xx-xx-xx ~]$ ping xxx.xxx.xx.xx(my local IP)
I have set all security groups(inbound), like All Trafic,All TCP and so on.
Sorry for bad English.
Thank You
Your computer (PC) cannot be pinged from an AWS hosted machine
This is probably because the VM on your computer is using NAT outbound to talk to the LAN, which goes to an Internet router, which sends the packets to AWS
The reverse route (inbound to your PC) does not exist so starting a ping echo request from a AWS machine will not work
It is possible to get around this by opening a pass through on your router but generally this is not a great idea
However if you want to make a socket connection securely there is a way
First, start a ssh session with remote port forwarding. In the Linux ssh client this is using the -R option.
For example, if your local system is running a listening service on port 80 and your remote system has the address of 54.10.10.10 then
ssh -R 8080:localhost:80 ec2-user#54.10.10.10
Will establish a circuit such that connections to the "localhost" on the remote ec2 server on port 8080 are connected to the "localhost" on port 80 of your local machine
If you are not using a ssh cli program, most ssh clients have a facility of this sort.
Note that it is necessary to keep the ssh session open to be able to use the connections
I have created an application in delphi and backend is postgres when i run the application i get the following error
general sql error.could not connect to the server;no
connection could be made because the target machine actively refused
it.[127.0.0.1:1:5433 alias resumep
I uninstalled it and installed it again but it didnt work.Even i changed the port number while installing .
I changed the password and installed again but its giving same error
what is the solution to this problem?
The database cluster of a standard PostgreSQL installation is listening on port 5432. (You can, of course, set up additional db clusters on different ports or configure your database cluster to listen on any other port.)
Any particular reason you try 5433? This is probably the cause of your problem.
If no server is listening on port 5433, the connection is simply not possible.