Question posted in 
I am trying to connect via the following php 7.4.1 test script to my remote database:
LOCAL
I have installed xampp on my ubuntu 16 machine and run the following script to test the connection via the ssh tunnel:
<?php
$mysqli = new mysqli("127.0.0.1", "root", "", "test_db", 13306);
/* check connection */
if ($mysqli->connect_errno) {
printf("Connect failed: %sn", $mysqli->connect_error);
exit();
}
/* check if server is alive */
if ($mysqli->ping()) {
printf ("Our connection is ok!n");
} else {
printf ("Error: %sn", $mysqli->error);
}
/* close connection */
$mysqli->close();
?>
My ssh-tunnel when executing the above file looks like the following:
admin@admin-VirtualBox:~$ ssh -v -v -v -i /home/admin/.ssh/id_rsa -N -L 13306:127.0.0.1:3306 [email protected]
OpenSSH_7.6p1 Ubuntu-4ubuntu0.3, OpenSSL 1.0.2n 7 Dec 2017
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug2: resolving "xx.xx.xxx.xxx" port 22
debug2: ssh_connect_direct: needpriv 0
debug1: Connecting to xx.xx.xxx.xxx [xx.xx.xxx.xxx] port 22.
debug1: Connection established.
debug1: identity file /home/admin/.ssh/id_rsa type 0
debug1: key_load_public: No such file or directory
debug1: identity file /home/admin/.ssh/id_rsa-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_7.6p1 Ubuntu-4ubuntu0.3
debug1: Remote protocol version 2.0, remote software version OpenSSH_8.2p1 Ubuntu-4ubuntu0.1
debug1: match: OpenSSH_8.2p1 Ubuntu-4ubuntu0.1 pat OpenSSH* compat 0x04000000
debug2: fd 3 setting O_NONBLOCK
debug1: Authenticating to xx.xx.xxx.xxx:22 as 'root'
debug3: hostkeys_foreach: reading file "/home/admin/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /home/admin/.ssh/known_hosts:1
debug3: load_hostkeys: loaded 1 keys from xx.xx.xxx.xxx
debug3: order_hostkeyalgs: prefer hostkeyalgs: [email protected],[email protected],[email protected],ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521
debug3: send packet: type 20
debug1: SSH2_MSG_KEXINIT sent
debug3: receive packet: type 20
debug1: SSH2_MSG_KEXINIT received
debug2: local client KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256,[email protected],ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha256,diffie-hellman-group14-sha1,ext-info-c
debug2: host key algorithms: [email protected],[email protected],[email protected],ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,[email protected],[email protected],ssh-ed25519,rsa-sha2-512,rsa-sha2-256,ssh-rsa
debug2: ciphers ctos: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected]
debug2: ciphers stoc: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected]
debug2: MACs ctos: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,[email protected],zlib
debug2: compression stoc: none,[email protected],zlib
debug2: languages ctos:
debug2: languages stoc:
debug2: first_kex_follows 0
debug2: reserved 0
debug2: peer server KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256,[email protected],ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group14-sha256
debug2: host key algorithms: rsa-sha2-512,rsa-sha2-256,ssh-rsa,ecdsa-sha2-nistp256,ssh-ed25519
debug2: ciphers ctos: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected]
debug2: ciphers stoc: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected]
debug2: MACs ctos: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,[email protected]
debug2: compression stoc: none,[email protected]
debug2: languages ctos:
debug2: languages stoc:
debug2: first_kex_follows 0
debug2: reserved 0
debug1: kex: algorithm: curve25519-sha256
debug1: kex: host key algorithm: ecdsa-sha2-nistp256
debug1: kex: server->client cipher: [email protected] MAC: <implicit> compression: none
debug1: kex: client->server cipher: [email protected] MAC: <implicit> compression: none
debug3: send packet: type 30
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug3: receive packet: type 31
debug1: Server host key: ecdsa-sha2-nistp256 SHA256:aaaaaaaaaaaaaaaaaaaaa/aaaaaaaaaaaaaaaaaaaaa
debug3: hostkeys_foreach: reading file "/home/admin/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /home/admin/.ssh/known_hosts:1
debug3: load_hostkeys: loaded 1 keys from xx.xx.xxx.xxx
debug1: Host 'xx.xx.xxx.xxx' is known and matches the ECDSA host key.
debug1: Found key in /home/admin/.ssh/known_hosts:1
debug3: send packet: type 21
debug2: set_newkeys: mode 1
debug1: rekey after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug3: receive packet: type 21
debug1: SSH2_MSG_NEWKEYS received
debug2: set_newkeys: mode 0
debug1: rekey after 134217728 blocks
debug2: key: /home/admin/.ssh/id_rsa (0x55d7cd2a7400), explicit, agent
debug3: send packet: type 5
debug3: receive packet: type 7
debug1: SSH2_MSG_EXT_INFO received
debug1: kex_input_ext_info: server-sig-algs=<ssh-ed25519,[email protected],ssh-rsa,rsa-sha2-256,rsa-sha2-512,ssh-dss,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,[email protected]>
debug3: receive packet: type 6
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug3: send packet: type 50
debug3: receive packet: type 51
debug1: Authentications that can continue: publickey,password
debug3: start over, passed a different list publickey,password
debug3: preferred gssapi-keyex,gssapi-with-mic,publickey,keyboard-interactive,password
debug3: authmethod_lookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethod_is_enabled publickey
debug1: Next authentication method: publickey
debug1: Offering public key: RSA SHA256:aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa /home/admin/.ssh/id_rsa
debug3: send_pubkey_test
debug3: send packet: type 50
debug2: we sent a publickey packet, wait for reply
debug3: receive packet: type 60
debug1: Server accepts key: pkalg rsa-sha2-512 blen 279
debug2: input_userauth_pk_ok: fp SHA256:aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
debug3: sign_and_send_pubkey: RSA SHA256:aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
debug3: send packet: type 50
debug3: receive packet: type 52
debug1: Authentication succeeded (publickey).
Authenticated to xx.xx.xxx.xxx ([xx.xx.xxx.xxx]:22).
debug1: Local connections to LOCALHOST:13306 forwarded to remote address 127.0.0.1:3306
debug3: channel_setup_fwd_listener_tcpip: type 2 wildcard 0 addr NULL
debug3: sock_set_v6only: set socket 5 IPV6_V6ONLY
debug1: Local forwarding listening on ::1 port 13306.
debug2: fd 5 setting O_NONBLOCK
debug3: fd 5 is O_NONBLOCK
debug1: channel 0: new [port listener]
debug1: Local forwarding listening on 127.0.0.1 port 13306.
debug2: fd 6 setting O_NONBLOCK
debug3: fd 6 is O_NONBLOCK
debug1: channel 1: new [port listener]
debug2: fd 3 setting TCP_NODELAY
debug3: ssh_packet_set_tos: set IP_TOS 0x10
debug1: Requesting [email protected]
debug3: send packet: type 80
debug1: Entering interactive session.
debug1: pledge: network
debug3: receive packet: type 80
debug1: client_input_global_request: rtype [email protected] want_reply 0
debug3: receive packet: type 4
debug1: Remote: /root/.ssh/authorized_keys:1: key options: agent-forwarding port-forwarding pty user-rc x11-forwarding
debug3: receive packet: type 4
debug1: Remote: /root/.ssh/authorized_keys:1: key options: agent-forwarding port-forwarding pty user-rc x11-forwarding
debug1: Connection to port 13306 forwarding to 127.0.0.1 port 3306 requested.
debug2: fd 7 setting TCP_NODELAY
debug2: fd 7 setting O_NONBLOCK
debug3: fd 7 is O_NONBLOCK
debug1: channel 2: new [direct-tcpip]
debug3: send packet: type 90
debug3: receive packet: type 91
debug2: channel 2: open confirm rwindow 2097152 rmax 32768
debug3: receive packet: type 96
debug2: channel 2: rcvd eof
debug2: channel 2: output open -> drain
debug2: channel 2: obuf empty
debug2: channel 2: close_write
debug2: channel 2: output drain -> closed
debug2: channel 2: read<=0 rfd 7 len 0
debug2: channel 2: read failed
debug2: channel 2: close_read
debug2: channel 2: input open -> drain
debug2: channel 2: ibuf empty
debug2: channel 2: send eof
debug3: send packet: type 96
debug2: channel 2: input drain -> closed
debug2: channel 2: send close
debug3: send packet: type 97
debug3: channel 2: will not send data after close
debug3: receive packet: type 97
debug2: channel 2: rcvd close
debug3: channel 2: will not send data after close
debug2: channel 2: is dead
debug2: channel 2: garbage collecting
debug1: channel 2: free: direct-tcpip: listening port 13306 for 127.0.0.1 port 3306, connect from 127.0.0.1 port 36828 to 127.0.0.1 port 13306, nchannels 3
debug3: channel 2: status: The following connections are open:
#2 direct-tcpip: listening port 13306 for 127.0.0.1 port 3306, connect from 127.0.0.1 port 36828 to 127.0.0.1 port 13306 (t4 r0 i3/0 o3/0 fd 7/7 cc -1)
REMOTE
The mysql-server is clearly running:
root@ubuntu-2gb-nbg1-1:~# netstat -tlpn | grep mysql
tcp 0 0 127.0.0.1:33060 0.0.0.0:* LISTEN 457519/mysqld
tcp 0 0 127.0.0.1:3306 0.0.0.0:* LISTEN 457519/mysqld
I have the following configuration for VARIABLES, when running SHOW VARIABLES LIKE '%time%'; I get:
binlog_max_flush_queue_time 0
connect_timeout 90
default_password_lifetime 0
delayed_insert_timeout 300
explicit_defaults_for_timestamp ON
flush_time 0
have_statement_timeout YES
innodb_flush_log_at_timeout 1
innodb_lock_wait_timeout 50
innodb_old_blocks_time 1000
innodb_rollback_on_timeout OFF
interactive_timeout 300
lc_time_names en_US
lock_wait_timeout 31536000
log_timestamps UTC
long_query_time 10.000000
max_execution_time 0
mysqlx_connect_timeout 30
mysqlx_idle_worker_thread_timeout 60
mysqlx_interactive_timeout 28800
mysqlx_port_open_timeout 0
mysqlx_read_timeout 30
mysqlx_wait_timeout 28800
mysqlx_write_timeout 60
net_read_timeout 90
net_write_timeout 90
original_commit_timestamp 36028797018963968
regexp_time_limit 32
rpl_stop_slave_timeout 31536000
slave_net_timeout 60
slow_launch_time 2
system_time_zone CET
time_zone SYSTEM
timestamp 1614522618.931326
wait_timeout 300
My firewall rules look like the following:
root@ubuntu-2gb-nbg1-1:~# sudo ufw status verbose
Status: active
Logging: on (low)
Default: deny (incoming), allow (outgoing), disabled (routed)
New profiles: skip
To Action From
-- ------ ----
80/tcp (Nginx HTTP) ALLOW IN Anywhere
22/tcp ALLOW IN Anywhere
22/tcp (OpenSSH) ALLOW IN Anywhere
127.0.0.1 3306/tcp ALLOW IN 127.0.0.1
80/tcp (Nginx HTTP (v6)) ALLOW IN Anywhere (v6)
22/tcp (v6) ALLOW IN Anywhere (v6)
22/tcp (OpenSSH (v6)) ALLOW IN Anywhere (v6)
However, when executing the local php script I get:
Any suggestions what I am doing wrong?
I appreciate your replies!
UPDATE
My my.cnf looks like the following:
#
# The MySQL database server configuration file.
#
# You can copy this to one of:
# - "/etc/mysql/my.cnf" to set global options,
# - "~/.my.cnf" to set user-specific options.
#
# One can use all long options that the program supports.
# Run program with --help to get a list of available options and with
# --print-defaults to see which it would actually understand and use.
#
# For explanations see
# http://dev.mysql.com/doc/mysql/en/server-system-variables.html
#
# * IMPORTANT: Additional settings that can override those from this file!
# The files must end with '.cnf', otherwise they'll be ignored.
#
!includedir /etc/mysql/conf.d/
!includedir /etc/mysql/mysql.conf.d/
My mysqld.cnf in the folder /etc/mysql/mysql.conf.d looks like the following:
#
# The MySQL database server configuration file.
#
# One can use all long options that the program supports.
# Run program with --help to get a list of available options and with
# --print-defaults to see which it would actually understand and use.
#
# For explanations see
# http://dev.mysql.com/doc/mysql/en/server-system-variables.html
# Here is entries for some specific programs
# The following values assume you have at least 32M ram
[mysqld]
#
# * Basic Settings
#
user = mysql
# pid-file = /var/run/mysqld/mysqld.pid
# socket = /var/run/mysqld/mysqld.sock
# port = 3306
# datadir = /var/lib/mysql
# If MySQL is running as a replication slave, this should be
# changed. Ref https://dev.mysql.com/doc/refman/8.0/en/server-system-variables.html#sysvar_tmpdir
# tmpdir = /tmp
#
# 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
mysqlx-bind-address = 127.0.0.1
#
# * Fine Tuning
#
key_buffer_size = 16M
max_allowed_packet = 1024M
# thread_stack = 256K
# thread_cache_size = -1
# This replaces the startup script and checks MyISAM tables if needed
# the first time they are touched
myisam-recover-options = BACKUP
# max_connections = 151
# table_open_cache = 4000
#
# * Logging and Replication
#
# Both location gets rotated by the cronjob.
#
# Log all queries
# Be aware that this log type is a performance killer.
# general_log_file = /var/log/mysql/query.log
# general_log = 1
#
# Error log - should be very few entries.
#
log_error = /var/log/mysql/error.log
#
# Here you can see queries with especially long duration
# slow_query_log = 1
# slow_query_log_file = /var/log/mysql/mysql-slow.log
# long_query_time = 2
# log-queries-not-using-indexes
#
# The following can be used as easy to replay backup logs or for replication.
# note: if you are setting up a replication slave, see README.Debian about
# other settings you may need to change.
# server-id = 1
# log_bin = /var/log/mysql/mysql-bin.log
# binlog_expire_logs_seconds = 2592000
max_binlog_size = 100M
# binlog_do_db = include_database_name
# binlog_ignore_db = include_database_name
# my settings
net_read_timeout=90
net_write_timeout=90
interactive_timeout=300
connect_timeout=90
innodb_log_file_size = 128M
log_error_verbosity = 3
My mysqldump.cnf in the folder /etc/mysql/conf.d looks like the following:
[mysqldump]
quick
quote-names
max_allowed_packet = 16M
3
Answers
This OpenSSH version is used on Ubuntu 20.04. Ubuntu 20.04 / MySQL 8 server for root user uses
auth_socketauthentication plugin by default. Did you change it tomysql_native_password?It looks like the ssh tunnel is not pointing to the
REMOTEmysql server, but to aLOCALmysql server instead, listening on port 3306 on the local machine.All the advises on mysql configuration, grants, and what not might become handy to debug the next failure point if any, but first thing first, the socket connection from the client to the server should point to the proper server.
Once the tunnel actually points to the remote server, a useful tool to inspect root causes for connections failure is the performance schema host_cache table.
See the manual:
https://dev.mysql.com/doc/refman/8.0/en/performance-schema-host-cache-table.html
Suggestions given above are valid and user permissions need to change but
I think you need to check this for remote access for more clarity:
MySQL: How to allow remote connection to mysql
Here in the config bind address assigned is 127.0.0.1 which you need to change either to:
When we configure mysql server , we need to change/add permissions and the bind address.
Update:
You can check whether you have privileges as the user you are trying to connect
For all I modified the data using the following
For particular IP
Update the IP
and do not forget to flush privileges
For bind address:
You can check if it is commented out in
/etc/mysql/mysql.conf.d/mysqld.cnfthen you need to restart mysql server