TNS connection forward
There are 3 machines as follows:
Machine A - Remote Exadata DB machine
Machine B - Remote machine from which only I can connect to port 1521 of Machine A
Machine C - Local Machine (To run SQL Developer and can't connect machineA directly)
Machine D - Bastion Server through which I connect to Machine B
Machine C can access service running in Machine B only using SSH tunnelling.
Is there any way I can access the Exadata DB from Machine A using SQL Developer running in Machine C?
I am trying this way:
ssh MachineD -L 15219:MachineB:15220 -L 15220:MachineA:1521
which is not working.
linux oracle-12c remote sysdba ssh
edited Jan 31 '18 at 8:34
miracle173
6,5271837
asked Jan 30 '18 at 12:11
kumarprdkumarprd
1045
bumped to the homepage by Community♦ 13 mins ago
This question has answers that may be good or bad; the system has marked it active so that they can be reviewed.
add a comment |
There are 3 machines as follows:
Machine A - Remote Exadata DB machine
Machine B - Remote machine from which only I can connect to port 1521 of Machine A
Machine C - Local Machine (To run SQL Developer and can't connect machineA directly)
Machine D - Bastion Server through which I connect to Machine B
Machine C can access service running in Machine B only using SSH tunnelling.
Is there any way I can access the Exadata DB from Machine A using SQL Developer running in Machine C?
I am trying this way:
ssh MachineD -L 15219:MachineB:15220 -L 15220:MachineA:1521
which is not working.
linux oracle-12c remote sysdba ssh
edited Jan 31 '18 at 8:34
miracle173
6,5271837
asked Jan 30 '18 at 12:11
kumarprdkumarprd
1045
bumped to the homepage by Community♦ 13 mins ago
This question has answers that may be good or bad; the system has marked it active so that they can be reviewed.
how do you connect ti the exadata at the moment. Using sqlplus from machine B? If so, how do you connect to machine B?
– miracle173
Jan 31 '18 at 8:31
@miracle173 yes , using sqlplus from machineB, From MachineC I use this: ssh MachineD -W MachineB:22 to login
– kumarprd
Feb 1 '18 at 11:00
did my solution work?
– miracle173
Feb 7 '18 at 3:23
@miracle173, thank you for the detailed solution. Actually I am seeing some firewall issue, where connection is getting refused while accessing the port after creating the tunnel.
– kumarprd
Feb 12 '18 at 15:29
add a comment |
There are 3 machines as follows:
Machine A - Remote Exadata DB machine
Machine B - Remote machine from which only I can connect to port 1521 of Machine A
Machine C - Local Machine (To run SQL Developer and can't connect machineA directly)
Machine D - Bastion Server through which I connect to Machine B
Machine C can access service running in Machine B only using SSH tunnelling.
Is there any way I can access the Exadata DB from Machine A using SQL Developer running in Machine C?
I am trying this way:
ssh MachineD -L 15219:MachineB:15220 -L 15220:MachineA:1521
which is not working.
linux oracle-12c remote sysdba ssh
edited Jan 31 '18 at 8:34
miracle173
6,5271837
asked Jan 30 '18 at 12:11
kumarprdkumarprd
1045
There are 3 machines as follows:
Machine A - Remote Exadata DB machine
Machine B - Remote machine from which only I can connect to port 1521 of Machine A
Machine C - Local Machine (To run SQL Developer and can't connect machineA directly)
Machine D - Bastion Server through which I connect to Machine B
Machine C can access service running in Machine B only using SSH tunnelling.
Is there any way I can access the Exadata DB from Machine A using SQL Developer running in Machine C?
I am trying this way:
ssh MachineD -L 15219:MachineB:15220 -L 15220:MachineA:1521
which is not working.
linux oracle-12c remote sysdba ssh
linux oracle-12c remote sysdba ssh
edited Jan 31 '18 at 8:34
miracle173
6,5271837
asked Jan 30 '18 at 12:11
kumarprdkumarprd
1045
edited Jan 31 '18 at 8:34
miracle173
6,5271837
asked Jan 30 '18 at 12:11
kumarprdkumarprd
1045
edited Jan 31 '18 at 8:34
miracle173
6,5271837
edited Jan 31 '18 at 8:34
miracle173
6,5271837
edited Jan 31 '18 at 8:34
miracle173
6,5271837
6,5271837
asked Jan 30 '18 at 12:11
kumarprdkumarprd
1045
asked Jan 30 '18 at 12:11
kumarprdkumarprd
1045
asked Jan 30 '18 at 12:11
kumarprdkumarprd
1045
1045
bumped to the homepage by Community♦ 13 mins ago
This question has answers that may be good or bad; the system has marked it active so that they can be reviewed.
bumped to the homepage by Community♦ 13 mins ago
This question has answers that may be good or bad; the system has marked it active so that they can be reviewed.
how do you connect ti the exadata at the moment. Using sqlplus from machine B? If so, how do you connect to machine B?
– miracle173
Jan 31 '18 at 8:31
@miracle173 yes , using sqlplus from machineB, From MachineC I use this: ssh MachineD -W MachineB:22 to login
– kumarprd
Feb 1 '18 at 11:00
did my solution work?
– miracle173
Feb 7 '18 at 3:23
@miracle173, thank you for the detailed solution. Actually I am seeing some firewall issue, where connection is getting refused while accessing the port after creating the tunnel.
– kumarprd
Feb 12 '18 at 15:29
add a comment |
how do you connect ti the exadata at the moment. Using sqlplus from machine B? If so, how do you connect to machine B?
– miracle173
Jan 31 '18 at 8:31
@miracle173 yes , using sqlplus from machineB, From MachineC I use this: ssh MachineD -W MachineB:22 to login
– kumarprd
Feb 1 '18 at 11:00
did my solution work?
– miracle173
Feb 7 '18 at 3:23
@miracle173, thank you for the detailed solution. Actually I am seeing some firewall issue, where connection is getting refused while accessing the port after creating the tunnel.
– kumarprd
Feb 12 '18 at 15:29
how do you connect ti the exadata at the moment. Using sqlplus from machine B? If so, how do you connect to machine B?
– miracle173
Jan 31 '18 at 8:31
how do you connect ti the exadata at the moment. Using sqlplus from machine B? If so, how do you connect to machine B?
– miracle173
Jan 31 '18 at 8:31
@miracle173 yes , using sqlplus from machineB, From MachineC I use this: ssh MachineD -W MachineB:22 to login
– kumarprd
Feb 1 '18 at 11:00
@miracle173 yes , using sqlplus from machineB, From MachineC I use this: ssh MachineD -W MachineB:22 to login
– kumarprd
Feb 1 '18 at 11:00
did my solution work?
– miracle173
Feb 7 '18 at 3:23
did my solution work?
– miracle173
Feb 7 '18 at 3:23
@miracle173, thank you for the detailed solution. Actually I am seeing some firewall issue, where connection is getting refused while accessing the port after creating the tunnel.
– kumarprd
Feb 12 '18 at 15:29
@miracle173, thank you for the detailed solution. Actually I am seeing some firewall issue, where connection is getting refused while accessing the port after creating the tunnel.
– kumarprd
Feb 12 '18 at 15:29
add a comment |
2 Answers
2
active
oldest
votes
You said it yourself: SSH tunneling.
On machine C:
ssh -L 12345:machineA:1521 machineB
Then use localhost:12345 in SQL Developer.
With the above, you log in to Machine B from Machine C using SSH, and create a tunnel to the listener port of Machine A through Machine B.
answered Jan 30 '18 at 12:51
Balazs PappBalazs Papp
26.2k2931
To create a tunnel from MachineC to MachineB I have to use a bastion server. e.g. ssh <bastion> -L 12345:MachineB:<serviceport> , then . how to use MachineA here ?
– kumarprd
Jan 30 '18 at 15:42
@kumarprd If you have another question then post a new question
– miracle173
Jan 30 '18 at 18:33
@miracle173 this reply is related to the same question, if you have read it. I just mentioned the step, that I use to create the tunnel, as the step in the answer is not helping.
– kumarprd
Jan 30 '18 at 19:23
@kumarprd even if it is related it is a different one. So why not follow the policy of this site and post another question?
– miracle173
Jan 30 '18 at 20:54
@miracle173 its not different at all. Try to understand the question and reply.
– kumarprd
Jan 31 '18 at 5:00
|
show 2 more comments
You tried
ssh MachineD -L 15219:MachineB:15220 -L 15220:MachineA:1521
this did not work but you think in the right direction, you want to join two tunnels.
login to MachineD and make a tunnel from your MachineB port 15219 to MachineB port 15220
ssh -L 15219:MachineD:15220 MachineD
So If you now send something to MachineC port 15219 then your ssh session (from MachineC to MachineD) sends it to MachineD port 15220
if you do a
tnsping '(DESCRIPTION =(ADDRESS = (PROTOCOL = TCP)(HOST = MachineC)(PORT = 15219))(CONNECT_DATA = (SERVICE_NAME = ORCL)))'
you will get an error message
TNS-12541: TNS:no listener
or something similar, if you try to connect with SQL Developer.
Because if you now send something to MachineC port 15219 then your ssh session (from MachineC to MachineD) sends it to MachineD port 15220. And on MachineD port 15220 there is actually nobody listening.
Now in your ssh session on MachineD execute the following command
ssh -L 15220:MachineA:1521 MachineB
Now you have opened an ssh session from MachineC to MachineB and data sent to MachineD port 15220 is read by this second ssh session and sent to MachineA port 1521. So you have two ssh sessions and the second one extends the first one.
But instead of opening one ssh session and in this ssh session opneing the other one you can do this in one command
ssh -L 15219:MachineD:15220 MachineD ssh -L 15220:MachineA:1521 MachineB
by juxtaposing both commands. If after an ssh command follows another comman this command is executed after login.
To avoid an error message like
Pseudo-terminal will not be allocated because stdin is not a terminal.
you can use the -T option for the second `ssh`` command.
ssh -L 15219:MachineD:15220 MachineD ssh -T -L 15220:MachineA:1521 MachineB
If you get some
bind: Address already in use
channel_setup_fwd_listener: cannot listen to port: 15220
messages then change the adresses.
e.g. use 15221 instead of 15220. Of course you must replace it on both posisitions:
ssh -L 15219:MachineD:15221 MachineD ssh -T -L 15221:MachineA:1521 MachineB
I hope this works. It is possible to configure the ssh daemons such that local forwarding is not allowed.
You cann concatenate an arbitrary number of tunnels .
I cannot test the -W option because I get
SSH-2.0-OpenSSH_5.3
Protocol mismatch.
answered Feb 1 '18 at 18:02
miracle173miracle173
6,5271837
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
You said it yourself: SSH tunneling.
On machine C:
ssh -L 12345:machineA:1521 machineB
Then use localhost:12345 in SQL Developer.
With the above, you log in to Machine B from Machine C using SSH, and create a tunnel to the listener port of Machine A through Machine B.
answered Jan 30 '18 at 12:51
Balazs PappBalazs Papp
26.2k2931
To create a tunnel from MachineC to MachineB I have to use a bastion server. e.g. ssh <bastion> -L 12345:MachineB:<serviceport> , then . how to use MachineA here ?
– kumarprd
Jan 30 '18 at 15:42
@kumarprd If you have another question then post a new question
– miracle173
Jan 30 '18 at 18:33
@miracle173 this reply is related to the same question, if you have read it. I just mentioned the step, that I use to create the tunnel, as the step in the answer is not helping.
– kumarprd
Jan 30 '18 at 19:23
@kumarprd even if it is related it is a different one. So why not follow the policy of this site and post another question?
– miracle173
Jan 30 '18 at 20:54
@miracle173 its not different at all. Try to understand the question and reply.
– kumarprd
Jan 31 '18 at 5:00
|
show 2 more comments
You said it yourself: SSH tunneling.
On machine C:
ssh -L 12345:machineA:1521 machineB
Then use localhost:12345 in SQL Developer.
With the above, you log in to Machine B from Machine C using SSH, and create a tunnel to the listener port of Machine A through Machine B.
answered Jan 30 '18 at 12:51
Balazs PappBalazs Papp
26.2k2931
To create a tunnel from MachineC to MachineB I have to use a bastion server. e.g. ssh <bastion> -L 12345:MachineB:<serviceport> , then . how to use MachineA here ?
– kumarprd
Jan 30 '18 at 15:42
@kumarprd If you have another question then post a new question
– miracle173
Jan 30 '18 at 18:33
@miracle173 this reply is related to the same question, if you have read it. I just mentioned the step, that I use to create the tunnel, as the step in the answer is not helping.
– kumarprd
Jan 30 '18 at 19:23
@kumarprd even if it is related it is a different one. So why not follow the policy of this site and post another question?
– miracle173
Jan 30 '18 at 20:54
@miracle173 its not different at all. Try to understand the question and reply.
– kumarprd
Jan 31 '18 at 5:00
|
show 2 more comments
You said it yourself: SSH tunneling.
On machine C:
ssh -L 12345:machineA:1521 machineB
Then use localhost:12345 in SQL Developer.
With the above, you log in to Machine B from Machine C using SSH, and create a tunnel to the listener port of Machine A through Machine B.
answered Jan 30 '18 at 12:51
Balazs PappBalazs Papp
26.2k2931
You said it yourself: SSH tunneling.
On machine C:
ssh -L 12345:machineA:1521 machineB
Then use localhost:12345 in SQL Developer.
With the above, you log in to Machine B from Machine C using SSH, and create a tunnel to the listener port of Machine A through Machine B.
answered Jan 30 '18 at 12:51
Balazs PappBalazs Papp
26.2k2931
answered Jan 30 '18 at 12:51
Balazs PappBalazs Papp
26.2k2931
answered Jan 30 '18 at 12:51
Balazs PappBalazs Papp
26.2k2931
answered Jan 30 '18 at 12:51
Balazs PappBalazs Papp
26.2k2931
26.2k2931
To create a tunnel from MachineC to MachineB I have to use a bastion server. e.g. ssh <bastion> -L 12345:MachineB:<serviceport> , then . how to use MachineA here ?
– kumarprd
Jan 30 '18 at 15:42
@kumarprd If you have another question then post a new question
– miracle173
Jan 30 '18 at 18:33
@miracle173 this reply is related to the same question, if you have read it. I just mentioned the step, that I use to create the tunnel, as the step in the answer is not helping.
– kumarprd
Jan 30 '18 at 19:23
@kumarprd even if it is related it is a different one. So why not follow the policy of this site and post another question?
– miracle173
Jan 30 '18 at 20:54
@miracle173 its not different at all. Try to understand the question and reply.
– kumarprd
Jan 31 '18 at 5:00
|
show 2 more comments
To create a tunnel from MachineC to MachineB I have to use a bastion server. e.g. ssh <bastion> -L 12345:MachineB:<serviceport> , then . how to use MachineA here ?
– kumarprd
Jan 30 '18 at 15:42
@kumarprd If you have another question then post a new question
– miracle173
Jan 30 '18 at 18:33
@miracle173 this reply is related to the same question, if you have read it. I just mentioned the step, that I use to create the tunnel, as the step in the answer is not helping.
– kumarprd
Jan 30 '18 at 19:23
@kumarprd even if it is related it is a different one. So why not follow the policy of this site and post another question?
– miracle173
Jan 30 '18 at 20:54
@miracle173 its not different at all. Try to understand the question and reply.
– kumarprd
Jan 31 '18 at 5:00
To create a tunnel from MachineC to MachineB I have to use a bastion server. e.g. ssh <bastion> -L 12345:MachineB:<serviceport> , then . how to use MachineA here ?
– kumarprd
Jan 30 '18 at 15:42
To create a tunnel from MachineC to MachineB I have to use a bastion server. e.g. ssh <bastion> -L 12345:MachineB:<serviceport> , then . how to use MachineA here ?
– kumarprd
Jan 30 '18 at 15:42
@kumarprd If you have another question then post a new question
– miracle173
Jan 30 '18 at 18:33
@kumarprd If you have another question then post a new question
– miracle173
Jan 30 '18 at 18:33
@miracle173 this reply is related to the same question, if you have read it. I just mentioned the step, that I use to create the tunnel, as the step in the answer is not helping.
– kumarprd
Jan 30 '18 at 19:23
@miracle173 this reply is related to the same question, if you have read it. I just mentioned the step, that I use to create the tunnel, as the step in the answer is not helping.
– kumarprd
Jan 30 '18 at 19:23
@kumarprd even if it is related it is a different one. So why not follow the policy of this site and post another question?
– miracle173
Jan 30 '18 at 20:54
@kumarprd even if it is related it is a different one. So why not follow the policy of this site and post another question?
– miracle173
Jan 30 '18 at 20:54
@miracle173 its not different at all. Try to understand the question and reply.
– kumarprd
Jan 31 '18 at 5:00
@miracle173 its not different at all. Try to understand the question and reply.
– kumarprd
Jan 31 '18 at 5:00
|
show 2 more comments
You tried
ssh MachineD -L 15219:MachineB:15220 -L 15220:MachineA:1521
this did not work but you think in the right direction, you want to join two tunnels.
login to MachineD and make a tunnel from your MachineB port 15219 to MachineB port 15220
ssh -L 15219:MachineD:15220 MachineD
So If you now send something to MachineC port 15219 then your ssh session (from MachineC to MachineD) sends it to MachineD port 15220
if you do a
tnsping '(DESCRIPTION =(ADDRESS = (PROTOCOL = TCP)(HOST = MachineC)(PORT = 15219))(CONNECT_DATA = (SERVICE_NAME = ORCL)))'
you will get an error message
TNS-12541: TNS:no listener
or something similar, if you try to connect with SQL Developer.
Because if you now send something to MachineC port 15219 then your ssh session (from MachineC to MachineD) sends it to MachineD port 15220. And on MachineD port 15220 there is actually nobody listening.
Now in your ssh session on MachineD execute the following command
ssh -L 15220:MachineA:1521 MachineB
Now you have opened an ssh session from MachineC to MachineB and data sent to MachineD port 15220 is read by this second ssh session and sent to MachineA port 1521. So you have two ssh sessions and the second one extends the first one.
But instead of opening one ssh session and in this ssh session opneing the other one you can do this in one command
ssh -L 15219:MachineD:15220 MachineD ssh -L 15220:MachineA:1521 MachineB
by juxtaposing both commands. If after an ssh command follows another comman this command is executed after login.
To avoid an error message like
Pseudo-terminal will not be allocated because stdin is not a terminal.
you can use the -T option for the second `ssh`` command.
ssh -L 15219:MachineD:15220 MachineD ssh -T -L 15220:MachineA:1521 MachineB
If you get some
bind: Address already in use
channel_setup_fwd_listener: cannot listen to port: 15220
messages then change the adresses.
e.g. use 15221 instead of 15220. Of course you must replace it on both posisitions:
ssh -L 15219:MachineD:15221 MachineD ssh -T -L 15221:MachineA:1521 MachineB
I hope this works. It is possible to configure the ssh daemons such that local forwarding is not allowed.
You cann concatenate an arbitrary number of tunnels .
I cannot test the -W option because I get
SSH-2.0-OpenSSH_5.3
Protocol mismatch.
answered Feb 1 '18 at 18:02
miracle173miracle173
6,5271837
add a comment |
You tried
ssh MachineD -L 15219:MachineB:15220 -L 15220:MachineA:1521
this did not work but you think in the right direction, you want to join two tunnels.
login to MachineD and make a tunnel from your MachineB port 15219 to MachineB port 15220
ssh -L 15219:MachineD:15220 MachineD
So If you now send something to MachineC port 15219 then your ssh session (from MachineC to MachineD) sends it to MachineD port 15220
if you do a
tnsping '(DESCRIPTION =(ADDRESS = (PROTOCOL = TCP)(HOST = MachineC)(PORT = 15219))(CONNECT_DATA = (SERVICE_NAME = ORCL)))'
you will get an error message
TNS-12541: TNS:no listener
or something similar, if you try to connect with SQL Developer.
Because if you now send something to MachineC port 15219 then your ssh session (from MachineC to MachineD) sends it to MachineD port 15220. And on MachineD port 15220 there is actually nobody listening.
Now in your ssh session on MachineD execute the following command
ssh -L 15220:MachineA:1521 MachineB
Now you have opened an ssh session from MachineC to MachineB and data sent to MachineD port 15220 is read by this second ssh session and sent to MachineA port 1521. So you have two ssh sessions and the second one extends the first one.
But instead of opening one ssh session and in this ssh session opneing the other one you can do this in one command
ssh -L 15219:MachineD:15220 MachineD ssh -L 15220:MachineA:1521 MachineB
by juxtaposing both commands. If after an ssh command follows another comman this command is executed after login.
To avoid an error message like
Pseudo-terminal will not be allocated because stdin is not a terminal.
you can use the -T option for the second `ssh`` command.
ssh -L 15219:MachineD:15220 MachineD ssh -T -L 15220:MachineA:1521 MachineB
If you get some
bind: Address already in use
channel_setup_fwd_listener: cannot listen to port: 15220
messages then change the adresses.
e.g. use 15221 instead of 15220. Of course you must replace it on both posisitions:
ssh -L 15219:MachineD:15221 MachineD ssh -T -L 15221:MachineA:1521 MachineB
I hope this works. It is possible to configure the ssh daemons such that local forwarding is not allowed.
You cann concatenate an arbitrary number of tunnels .
I cannot test the -W option because I get
SSH-2.0-OpenSSH_5.3
Protocol mismatch.
answered Feb 1 '18 at 18:02
miracle173miracle173
6,5271837
add a comment |
You tried
ssh MachineD -L 15219:MachineB:15220 -L 15220:MachineA:1521
this did not work but you think in the right direction, you want to join two tunnels.
login to MachineD and make a tunnel from your MachineB port 15219 to MachineB port 15220
ssh -L 15219:MachineD:15220 MachineD
So If you now send something to MachineC port 15219 then your ssh session (from MachineC to MachineD) sends it to MachineD port 15220
if you do a
tnsping '(DESCRIPTION =(ADDRESS = (PROTOCOL = TCP)(HOST = MachineC)(PORT = 15219))(CONNECT_DATA = (SERVICE_NAME = ORCL)))'
you will get an error message
TNS-12541: TNS:no listener
or something similar, if you try to connect with SQL Developer.
Because if you now send something to MachineC port 15219 then your ssh session (from MachineC to MachineD) sends it to MachineD port 15220. And on MachineD port 15220 there is actually nobody listening.
Now in your ssh session on MachineD execute the following command
ssh -L 15220:MachineA:1521 MachineB
Now you have opened an ssh session from MachineC to MachineB and data sent to MachineD port 15220 is read by this second ssh session and sent to MachineA port 1521. So you have two ssh sessions and the second one extends the first one.
But instead of opening one ssh session and in this ssh session opneing the other one you can do this in one command
ssh -L 15219:MachineD:15220 MachineD ssh -L 15220:MachineA:1521 MachineB
by juxtaposing both commands. If after an ssh command follows another comman this command is executed after login.
To avoid an error message like
Pseudo-terminal will not be allocated because stdin is not a terminal.
you can use the -T option for the second `ssh`` command.
ssh -L 15219:MachineD:15220 MachineD ssh -T -L 15220:MachineA:1521 MachineB
If you get some
bind: Address already in use
channel_setup_fwd_listener: cannot listen to port: 15220
messages then change the adresses.
e.g. use 15221 instead of 15220. Of course you must replace it on both posisitions:
ssh -L 15219:MachineD:15221 MachineD ssh -T -L 15221:MachineA:1521 MachineB
I hope this works. It is possible to configure the ssh daemons such that local forwarding is not allowed.
You cann concatenate an arbitrary number of tunnels .
I cannot test the -W option because I get
SSH-2.0-OpenSSH_5.3
Protocol mismatch.
answered Feb 1 '18 at 18:02
miracle173miracle173
6,5271837
You tried
ssh MachineD -L 15219:MachineB:15220 -L 15220:MachineA:1521
this did not work but you think in the right direction, you want to join two tunnels.
login to MachineD and make a tunnel from your MachineB port 15219 to MachineB port 15220
ssh -L 15219:MachineD:15220 MachineD
So If you now send something to MachineC port 15219 then your ssh session (from MachineC to MachineD) sends it to MachineD port 15220
if you do a
tnsping '(DESCRIPTION =(ADDRESS = (PROTOCOL = TCP)(HOST = MachineC)(PORT = 15219))(CONNECT_DATA = (SERVICE_NAME = ORCL)))'
you will get an error message
TNS-12541: TNS:no listener
or something similar, if you try to connect with SQL Developer.
Because if you now send something to MachineC port 15219 then your ssh session (from MachineC to MachineD) sends it to MachineD port 15220. And on MachineD port 15220 there is actually nobody listening.
Now in your ssh session on MachineD execute the following command
ssh -L 15220:MachineA:1521 MachineB
Now you have opened an ssh session from MachineC to MachineB and data sent to MachineD port 15220 is read by this second ssh session and sent to MachineA port 1521. So you have two ssh sessions and the second one extends the first one.
But instead of opening one ssh session and in this ssh session opneing the other one you can do this in one command
ssh -L 15219:MachineD:15220 MachineD ssh -L 15220:MachineA:1521 MachineB
by juxtaposing both commands. If after an ssh command follows another comman this command is executed after login.
To avoid an error message like
Pseudo-terminal will not be allocated because stdin is not a terminal.
you can use the -T option for the second `ssh`` command.
ssh -L 15219:MachineD:15220 MachineD ssh -T -L 15220:MachineA:1521 MachineB
If you get some
bind: Address already in use
channel_setup_fwd_listener: cannot listen to port: 15220
messages then change the adresses.
e.g. use 15221 instead of 15220. Of course you must replace it on both posisitions:
ssh -L 15219:MachineD:15221 MachineD ssh -T -L 15221:MachineA:1521 MachineB
I hope this works. It is possible to configure the ssh daemons such that local forwarding is not allowed.
You cann concatenate an arbitrary number of tunnels .
I cannot test the -W option because I get
SSH-2.0-OpenSSH_5.3
Protocol mismatch.
answered Feb 1 '18 at 18:02
miracle173miracle173
6,5271837
edited Feb 2 '18 at 6:06
answered Feb 1 '18 at 18:02
miracle173miracle173
6,5271837
answered Feb 1 '18 at 18:02
miracle173miracle173
6,5271837
answered Feb 1 '18 at 18:02
miracle173miracle173
6,5271837
6,5271837
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how do you connect ti the exadata at the moment. Using sqlplus from machine B? If so, how do you connect to machine B?
– miracle173
Jan 31 '18 at 8:31
@miracle173 yes , using sqlplus from machineB, From MachineC I use this: ssh MachineD -W MachineB:22 to login
– kumarprd
Feb 1 '18 at 11:00
did my solution work?
– miracle173
Feb 7 '18 at 3:23
@miracle173, thank you for the detailed solution. Actually I am seeing some firewall issue, where connection is getting refused while accessing the port after creating the tunnel.
– kumarprd
Feb 12 '18 at 15:29