Connection to <hostname>:5432 refused - java

I'm not a pro in communication networks, so I have no idea what should be my "hostname" and where can I find it?
I created a postgreSQL server on ubuntu 14.04, I can connect to it from the same computer without problem by setting hostname to 127.0.0.1(localhost), or even 192.168.1.42 (my private ip). But I can not connect to my server from any other computer, even if they are on local network or not. I always get this message:
"Connection to <hostname>:5432 refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections."
where is either 127.0.1.1, 127.0.0.1, 192.168.1.42, 98.765.432.123(public ip) or anything else, it never works.
What is the right hostname?
I already set listen_addresses to '*', already edited pg_hba.conf to accept 0.0.0.0/0 IP-s, and disabled ubuntu firewall.

This could be caused by many things.
The server has an IP address. That is the address that the JDBC connection string should use for <hostname>, unless you have some local DNS solution. To rule out problems with the latter, use the IP address of the Ubuntu server. On Ubuntu type ifconfig to see it; it probably is 192.168.1.42 like you mentioned. So from the client with the Java app, you use the IP address of the server.
If you have a standard PostgreSQL installation, it should use port 5432, you can check the setting in postgresql.conf. In the JDBC connection string you should also indicate the port: "jdbc:postgresql://192.168.1.42:5432/...", just to be on the safe side.
You need to have a database that you can connect to. Note that by default only the owner of the database (probably the user postgres in your case) can connect to it. See further down.
In pg_hba.conf you need to create an entry for your new database so it can be connected to (typical settings, check your network setup). The IP address (range) you specify here is that of the clients connecting to the database!
host my_db all 192.168.0.0/16 md5
You must restart your PostgreSQL server after modifying pg_hba.conf. (Typically on Ubuntu, do sudo ./etc/init.d/postgresql restart)
To create database my_db (or whatever name you prefer), go to your Ubuntu box and enter psql as the postgres user:
vekszor#ubuntu:~$ sudo -u postgres psql
[sudo] password for user:
psql (9.3.5)
Type "help" for help
postgres=#
In order to connect to the database, you should have a database:
postgres=# CREATE DATABASE my_db;
CREATE DATABASE
You also want a user (role) that is less powerful than the postgres superuser, but still able to manipulate the database. So create this user role and assign ownership of the database:
postgres=# CREATE ROLE vekszor LOGIN PASSWORD 'secret123' CREATEROLE;
CREATE ROLE
postgres=# ALTER DATABASE my_db OWNER TO vekszor;
ALTER
Now you can go back to your client computer with the Java app and finish the JDBC connection string with the name of the database, the user and password.
Note that if you want to access your database from the internet, you should set up a NAT rule in your router to point traffic on port 5432 to the IP of your Ubuntu server.So long as the internal address of the router is in the same address range of the client computers that you indicated in pg_hba.conf this should be easy to set up, otherwise add a new entry in pg_hba.conf.

Reading your comments to the correct answer:
This is how you add a rule to iptables:
iptables -A INPUT -s 0/0 -p tcp --dport 5432 -j ACCEPT
0/0: If you want anybody to access it. You can change it to a specific ip address or range of ip addresses.

If you are connected to the server using UI you can run the below query to get the IP Address of server using below query to verify if you are using the correct IP.
Select inet_server_addr();

Related

PHPMyAdmin access denied for user [duplicate]

MySQL 5.1.31 running on Windows XP.
From the local MySQL server (192.168.233.142) I can connect as root as follows:
>mysql --host=192.168.233.142 --user=root --password=redacted
From a remote machine (192.168.233.163), I can see that the mysql port is open:
# telnet 192.168.233.142 3306
Trying 192.168.233.142...
Connected to 192.168.233.142 (192.168.233.142).
But when trying to connect to mysql from the remote machine, I receive:
# mysql --host=192.168.233.142 --user=root --password=redacted
ERROR 1045 (28000): Access denied for user 'root'#'192.168.233.163' (using password: YES)
I have only 2 entries in mysql.user:
Host User Password
--------------------------------------
localhost root *blahblahblah
% root [same as above]
What more do I need to do to enable remote access?
EDIT
As suggested by Paulo below, I tried replacing the mysql.user entry for % with an IP specific entry, so my user table now looks like this:
Host User Password
------------------------------------------
localhost root *blahblahblah
192.168.233.163 root [same as above]
I then restarted the machine, but the problem persists.
You have to put this as root:
GRANT ALL PRIVILEGES ON *.* TO 'USERNAME'#'IP' IDENTIFIED BY 'PASSWORD' with grant option;
;
where IP is the IP you want to allow access, USERNAME is the user you use to connect, and PASSWORD is the relevant password.
If you want to allow access from any IP just put % instead of your IP
and then you only have to put
FLUSH PRIVILEGES;
Or restart mysql server and that's it.
I was getting the same error after granting remote access until I made this:
From /etc/mysql/my.cnf
In newer versions of mysql the location of the file is
/etc/mysql/mysql.conf.d/mysqld.cnf
# Instead of skip-networking the default is now to listen only on
# localhost which is more compatible and is not less secure.
#bind-address = 127.0.0.1
(comment this line: bind-address = 127.0.0.1)
Then run service mysql restart.
By default in MySQL server remote access is disabled. The process to provide a remote access to user is.
Go to my sql bin folder or add it to PATH
Login to root by mysql -uroot -proot (or whatever the root password is.)
On success you will get mysql>
Provide grant access all for that user.
GRANT ALL PRIVILEGES ON *.* TO 'username'#'IP' IDENTIFIED BY 'password';
Here IP is IP address for which you want to allow remote access, if we put % any IP address can access remotely.
Example:
C:\Users\UserName> cd C:\Program Files (x86)\MySQL\MySQL Server 5.0\bin
C:\Program Files (x86)\MySQL\MySQL Server 5.0\bin>mysql -uroot -proot
mysql> GRANT ALL PRIVILEGES ON *.* TO 'root'#'%' IDENTIFIED BY 'root';
Query OK, 0 rows affected (0.27 sec)
mysql> FLUSH PRIVILEGES;
Query OK, 0 rows affected (0.25 sec)
This for a other user.
mysql> GRANT ALL PRIVILEGES ON *.* TO 'testUser'#'%' IDENTIFIED BY 'testUser';
Query OK, 0 rows affected (0.00 sec)
mysql> FLUSH PRIVILEGES;
Query OK, 0 rows affected (0.00 sec)
Hope this will help
Paulo's help lead me to the solution. It was a combination of the following:
the password contained a dollar sign
I was trying to connect from a Linux shell
The bash shell treats the dollar sign as a special character for expansion to an environment variable, so we need to escape it with a backslash. Incidentally, we don't have to do this in the case where the dollar sign is the final character of the password.
As an example, if your password is "pas$word", from Linux bash we must connect as follows:
# mysql --host=192.168.233.142 --user=root --password=pas\$word
Do you have a firewall ? make sure that port 3306 is open.
On windows , by default mysql root account is created that is permitted to have access from localhost only unless you have selected the option to enable access from remote machines during installation .
creating or update the desired user with '%' as hostname .
example :
CREATE USER 'krish'#'%' IDENTIFIED BY 'password';
Try to flush privileges again.
Try to restart server to reload grants.
Try create a user with host "192.168.233.163". "%" appears to not allow all (it's weird)
In my case I was trying to connect to a remote mysql server on cent OS. After going through a lot of solutions (granting all privileges, removing ip bindings,enabling networking) problem was still not getting solved.
As it turned out, while looking into various solutions,I came across iptables, which made me realize mysql port 3306 was not accepting connections.
Here is a small note on how I checked and resolved this issue.
Checking if port is accepting connections:
telnet (mysql server ip) [portNo]
Adding ip table rule to allow connections on the port:
iptables -A INPUT -i eth0 -p tcp -m tcp --dport 3306 -j ACCEPT
Would not recommend this for production environment, but if your iptables are not configured properly, adding the rules might not still solve the issue. In that case following should be done:
service iptables stop
Hope this helps.
if you are using dynamic ip just grant access to 192.168.2.% so now you dont have to worry about granting access to your ip address every time.
I was struggling with remote login to MYSQL for my Amazon EC2 Linux instance. Found the solution was to make sure my security group included an inbound rule for MySQL port 3306 to include my IP address (or 0.0.0.0/0 for anywhere). Immediately could connect remotely as soon as I added this rule.
MySQL ODBC 3.51 Driver is that special characters in the password aren't handled.
"Warning – You might have a serious headache with MySQL ODBC 3.51 if the password in your GRANT command contains special characters, such as ! # # $ % ^ ?. MySQL ODBC 3.51 ODBC Driver does not support these special characters in the password box. The only error message you would receive is “Access denied” (using password: YES)" - from http://www.plaintutorials.com/install-and-create-mysql-odbc-connector-on-windows-7/
The user/host combination may have been created without password.
I was assuming that when adding a new host for an existing user (using a GUI app), the existing password would also be used for the new user/host combination.
I could log in with
mysql -u username -p PASSWORD
locally, but not from IPADDRESS with
mysql -u --host=HOST -p PASSWORD
(I could actually log in from IPADDRESS without using a password)
mysql -u --host=HOST
Setting the password allowed access:
set password for '<USER>'#'<IPADDRESS>' = '<PASSWORD>';
New location for mysql config file is
/etc/mysql/mysql.conf.d/mysqld.cnf
My case is absolutely simple.
You may have this problem in case if you type in WRONG password. No create user is needed (user already existed), no other permissions. Basically make sure that the password is correct. So make double-sure the password is correct

Spring Boot, using oracle-ldap url through ssh tunnel on local machine

There are 3 machines:
local -> some remote server -> oracle db server (via ldap)
I want to set up datasource connection (in my spring boot app) to the oracle db.
There is no direct connectivity between local machine and the one with oracle db.
So, i'm using the ssh tunnel through remote server:
ssh -L 127.0.0.1:8081:some.ldap.host:389 user#remote.server.host
In application.yml file i'm using further url:
spring:
datasource:
url: jdbc:oracle:thin:#ldap://127.0.0.1:8081//srvcnm,cn=OracleContext,dc=yy,dc=xx,dc=com
And when my app trying to get db connection, im getting the following error:
Caused by: oracle.net.nt.TimeoutInterruptHandler$IOReadTimeoutException: Socket read timed out
at oracle.net.nt.TimeoutSocketChannel.handleInterrupt(TimeoutSocketChannel.java:254)
at oracle.net.nt.TimeoutSocketChannel.connect(TimeoutSocketChannel.java:103)
at oracle.net.nt.TimeoutSocketChannel.<init>(TimeoutSocketChannel.java:77)
at oracle.net.nt.TcpNTAdapter.connect(TcpNTAdapter.java:192)
... 126 common frames omitted
Whenever i'm deploying app on the remote server and enter "direct" url in application.yml the connection is being obtained without any timeouts, and the app works well.
jdbc:oracle:thin:#ldap://some.ldap.host:389//srvcnm,cn=OracleContext,dc=yy,dc=xx,dc=com
Does anyone know how to handle this? How to get connection from local machine?
I may do some thing like this, I am going to create file call ~/.ssh/config then add following
Host remoteserver1
User usermane
Hostname ip or host name
ForwardAgent yes
Host oracleserver
User username
Hostname some.ldap.host
Port 22
# ForwardAgent yes if you need to forward one more instance
LocalForward 8081 some.ldap.host:389
ProxyCommand ssh -q -W %h:%p remoteserver1
What this does is that when I attempt to connect to ssh oracleserver from remoteserver1, it connects to hopper and then proxies the SSH connection to port 22 on overthere (ie: SSH on oracleserver).
now to connect via ssh do following ssh oracleserver , as it will make ssh tunnel between your machine and oracleserver via remoteserver1. along with port forwarding.
The problem was in redirecting source connection request to another machine with oracle db itself (after ldap auth).
So, the request's path looked like:
1.local -> 2.remote server -> 3.ldap server -> 4.oracle db server
There wasn't connectivity between 1st and 4th machine as the tunnel was only between 1th and 3rd one.
So, you if you faced this issue, you may add one more ssh tunnel (First tunnel is for ldap server, second one for oracle db) and enrich your "etc/hosts" with oracle server's routing.
In my case the issue was in access restrictions. The oracle server is filtering sockets somehow and grants access to certain machines.

Communications link failure when connecting to MySQL database from Java

If I specify a URL like jdbc:mysql://localhost/database, then it works. If I specify either a local or remote IP address it doesn't work. Do I need to change any network settings, etc? The platform is Ubuntu.
You need to use GRANT ALL PRIVILEGES in mysql to allow external ip address
see https://dev.mysql.com/doc/refman/5.1/en/grant.html
1) change my.conf (whatever your mysql conf file is called). And set bind-address to 0.0.0.0 as it is prob 127.0.0.1
2) stop/restart mysql daemon
3) add database user perhaps coming in from diff ip addr
CREATE USER 'fred7'#'192.168.2.7' IDENTIFIED BY 'my_password';
4) grants
GRANT ALL PRIVILEGES ON test7db.* TO 'fred7'#'192.168.2.7';
5) firewall
For 3 and 4, let's say the mysql server is on aws ec2 and i am sitting at a public library using sqlyog or workbench. That prog will alert me if connect failure stating something like connection failed for user 'fred7'#'gfs6.nyc.comcastbusiness.net'. So it is pretty obvious how to do 3 and 4 then.
Good luck!

JDBC Connection error to mysql Access Denied for user <user>#<host>

I have already checked the other Stack Overflow and web links on this:
MySQL is on a Linux server
Linux uslx600 2.6.32-358.14.1.el6.x86_64 #1 SMP Mon
Says its IP is 1.2.3.4
I can connect to it from my laptop using MySQL Workbench. I cannot attach image due to Stack Overflow policy, but the dialog is as follows:
Connection Method: tcp/ip
Hostname: <host of the server, so e.g. 1.2.3.4>
Port: 3306 <This is same port as mentioned below for JDBC connection>
username: bugs
Default Schema: bugs
Within that mysql I ran [select user(), current_user()], I get
user() = bugs#<my laptop IP>
current_user() = bugs#%
Now I am trying to connect from the Linux server where the MySQL database is.
Following works, user is user by itself, i.e. no "#%" or something:
conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/bugs", user, pasword);
Following also works:
conn = DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/bugs", user, pasword);
But it does not work, if I give the IP address of the box or hostname. And what I am really working towards is accessing this from another Linux server, which does not work either probably due to same issue.
The error message when it fails is:
Access Denied for user 'bugs'#'<hostname of the server>' (using password=YES)
If there was some access issue on the server, shouldn't the MySQL Workbench have the same issue?
And current_user() says bug#% so does it not imply that user is setup correctly?
I have also tried changing user to 'user'#'%' etc., but in all those cases error message was always:
'bugs'#'%'#'<hostname>'
Make sure you have granted all privileges to all hosts.
Check your my.cnf file and comment out bind-address if it's pointing to 127.0.0.1 only.
MySQL root access from all hosts
The error says that it cannot connect to the server with the given password. May be your password is incorrect or if it is having special characters, you have to escape that string properly.
Another thing, the user bugs could not have privilege to connect to the server from the specified host. Try providing GRANTS to the user from the host you are connecting and then check if you are able to connect to MySQL.
GRANT ALL PRIVILEGES ON *.* TO 'bugs'#'%' IDENTIFIED BY 'password';
or comment the line in my.cnf file
#bind-address = 127.0.0.1
restart mysql service.

How to connect with remote MySQL database?

so I tried to connect to my local host with the 3306 port, and it works fine. Now, I'm using my second computer to connect to the database remotely.
I use the jdbc:mysql://192.168.15.25:3306/yourdatabase type.
My two computers are actually using the same IP.
The trace says communication failure. I followed the problem, and it happens when I try to get the connection from the DriverManager.
I did not touch the firewall at all.
I did not write any permissions to users, as there are no users, just the admin.
Two computers can't have same IP. Check the second for IP address using ifconfig command (if you have *nix system).
Follow this instructions:
Client PC:(sample ip: 192.168.0.105 want yo connect to mysql server on 192.168.0.172)
- Java app: user: dbuser, pass: dbpass, host: 192.168.0.172
Mysql Server PC:
- On mysql console: GRANT ALL PRIVILEGES ON *.* TO dbuser#192.168.0.105 identified by "dbpass";
FLUSH PRIVILEGES;
Now you have all set to make a remote conection from your client to your mysql server.

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