SSH connection getting closed automatically after a sudo command











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I have two servers running the same version of RedHat 6.4, however one of them behaves differently when I run remote sudo commands through SSH on it. On server1, the connection is automatically closed after a successful sudo command, but on server3, the connection is kept open.



Note that for these tests the sudo user had the NOPASSWD flag so no prompt is asked. As far as I know, all configurations on these servers are the same (they were cloned).



I tested using this:



ssh -vvv user@server1 << EOF

sudo ls -l /home/

ls -l /home/

pwd

EOF


If I run this on server1 I get a single file listing.



debug3: Wrote 32 bytes for a total of 1621

total 40

drwxr-xr-x.  5 user       user       4096 Apr 26  2013 user

debug1: client_input_channel_req: channel 0 rtype exit-status reply 0

debug2: channel 0: rcvd eof

debug2: channel 0: output open -> drain


Running without the sudo command on the same server I get my two file listing and the pwd result 



ssh -vvv user@server1 << EOF

ls -l /home/

ls -l /home/

pwd

EOF


Result:



debug3: Wrote 32 bytes for a total of 1605

total 40

drwxr-xr-x.  5 user       user       4096 Apr 26  2013 user

total 40

drwxr-xr-x.  5 user       user       4096 Apr 26  2013 user

/home/user

debug1: client_input_channel_req: channel 0 rtype exit-status reply 0

debug2: channel 0: rcvd eof

debug2: channel 0: output open -> drain


However, running the script with the sudo command on server3 I get the result of all 3 commands like the previous test. I compared the output of the ssh -vvv logs from both servers (1 and 3) and everything seems the same except for a debug line in a different order when the connection is closed (see client_input... line).



server1 (same with or without sudo)



[command results]

debug1: client_input_channel_req: channel 0 rtype exit-status reply 0

debug2: channel 0: rcvd eof

debug2: channel 0: output open -> drain

debug2: channel 0: obuf empty

debug2: channel 0: close_write

debug2: channel 0: output drain -> closed

debug2: channel 0: rcvd close


server3



[command results]

debug2: channel 0: rcvd eof

debug2: channel 0: output open -> drain

debug2: channel 0: obuf empty

debug2: channel 0: close_write

debug2: channel 0: output drain -> closed

debug1: client_input_channel_req: channel 0 rtype exit-status reply 0

debug2: channel 0: rcvd close


I would like to know how to fix server1 so that the connection isn't automatically closed so that my script can execute completely when including sudo commands.






ssh rhel sudo







share|improve this question
























  • I wonder if errexit is being set?
    – Jeff Schaller
    yesterday






  • 1




    also, compare the /etc/sudoers files (including /etc/sudoers.d/*), keeping an eye out for any requiretty or !requiretty differences. Perhaps server3 has been configured to allow sudo without requiring a tty, and server1 has not. One way to test would be to modify the server 1 command from ssh -vvv user@server1 ... to ssh -t -vvv user@server1.... The -t option will force the allocation of a tty. If sudo works doing that, then it's a tty requirement stuffing you up.
    – Tim Kennedy
    yesterday












  • errexit is off (command is successful anyway). requiretty is commented out in the sudoers file and sudoers.d directory is empty.
    – Bibz
    yesterday

















up vote
0
down vote

favorite












I have two servers running the same version of RedHat 6.4, however one of them behaves differently when I run remote sudo commands through SSH on it. On server1, the connection is automatically closed after a successful sudo command, but on server3, the connection is kept open.



Note that for these tests the sudo user had the NOPASSWD flag so no prompt is asked. As far as I know, all configurations on these servers are the same (they were cloned).



I tested using this:



ssh -vvv user@server1 << EOF

sudo ls -l /home/

ls -l /home/

pwd

EOF


If I run this on server1 I get a single file listing.



debug3: Wrote 32 bytes for a total of 1621

total 40

drwxr-xr-x.  5 user       user       4096 Apr 26  2013 user

debug1: client_input_channel_req: channel 0 rtype exit-status reply 0

debug2: channel 0: rcvd eof

debug2: channel 0: output open -> drain


Running without the sudo command on the same server I get my two file listing and the pwd result 



ssh -vvv user@server1 << EOF

ls -l /home/

ls -l /home/

pwd

EOF


Result:



debug3: Wrote 32 bytes for a total of 1605

total 40

drwxr-xr-x.  5 user       user       4096 Apr 26  2013 user

total 40

drwxr-xr-x.  5 user       user       4096 Apr 26  2013 user

/home/user

debug1: client_input_channel_req: channel 0 rtype exit-status reply 0

debug2: channel 0: rcvd eof

debug2: channel 0: output open -> drain


However, running the script with the sudo command on server3 I get the result of all 3 commands like the previous test. I compared the output of the ssh -vvv logs from both servers (1 and 3) and everything seems the same except for a debug line in a different order when the connection is closed (see client_input... line).



server1 (same with or without sudo)



[command results]

debug1: client_input_channel_req: channel 0 rtype exit-status reply 0

debug2: channel 0: rcvd eof

debug2: channel 0: output open -> drain

debug2: channel 0: obuf empty

debug2: channel 0: close_write

debug2: channel 0: output drain -> closed

debug2: channel 0: rcvd close


server3



[command results]

debug2: channel 0: rcvd eof

debug2: channel 0: output open -> drain

debug2: channel 0: obuf empty

debug2: channel 0: close_write

debug2: channel 0: output drain -> closed

debug1: client_input_channel_req: channel 0 rtype exit-status reply 0

debug2: channel 0: rcvd close


I would like to know how to fix server1 so that the connection isn't automatically closed so that my script can execute completely when including sudo commands.






ssh rhel sudo







share|improve this question
























  • I wonder if errexit is being set?
    – Jeff Schaller
    yesterday






  • 1




    also, compare the /etc/sudoers files (including /etc/sudoers.d/*), keeping an eye out for any requiretty or !requiretty differences. Perhaps server3 has been configured to allow sudo without requiring a tty, and server1 has not. One way to test would be to modify the server 1 command from ssh -vvv user@server1 ... to ssh -t -vvv user@server1.... The -t option will force the allocation of a tty. If sudo works doing that, then it's a tty requirement stuffing you up.
    – Tim Kennedy
    yesterday












  • errexit is off (command is successful anyway). requiretty is commented out in the sudoers file and sudoers.d directory is empty.
    – Bibz
    yesterday















up vote
0
down vote

favorite









up vote
0
down vote

favorite











I have two servers running the same version of RedHat 6.4, however one of them behaves differently when I run remote sudo commands through SSH on it. On server1, the connection is automatically closed after a successful sudo command, but on server3, the connection is kept open.



Note that for these tests the sudo user had the NOPASSWD flag so no prompt is asked. As far as I know, all configurations on these servers are the same (they were cloned).



I tested using this:



ssh -vvv user@server1 << EOF

sudo ls -l /home/

ls -l /home/

pwd

EOF


If I run this on server1 I get a single file listing.



debug3: Wrote 32 bytes for a total of 1621

total 40

drwxr-xr-x.  5 user       user       4096 Apr 26  2013 user

debug1: client_input_channel_req: channel 0 rtype exit-status reply 0

debug2: channel 0: rcvd eof

debug2: channel 0: output open -> drain


Running without the sudo command on the same server I get my two file listing and the pwd result 



ssh -vvv user@server1 << EOF

ls -l /home/

ls -l /home/

pwd

EOF


Result:



debug3: Wrote 32 bytes for a total of 1605

total 40

drwxr-xr-x.  5 user       user       4096 Apr 26  2013 user

total 40

drwxr-xr-x.  5 user       user       4096 Apr 26  2013 user

/home/user

debug1: client_input_channel_req: channel 0 rtype exit-status reply 0

debug2: channel 0: rcvd eof

debug2: channel 0: output open -> drain


However, running the script with the sudo command on server3 I get the result of all 3 commands like the previous test. I compared the output of the ssh -vvv logs from both servers (1 and 3) and everything seems the same except for a debug line in a different order when the connection is closed (see client_input... line).



server1 (same with or without sudo)



[command results]

debug1: client_input_channel_req: channel 0 rtype exit-status reply 0

debug2: channel 0: rcvd eof

debug2: channel 0: output open -> drain

debug2: channel 0: obuf empty

debug2: channel 0: close_write

debug2: channel 0: output drain -> closed

debug2: channel 0: rcvd close


server3



[command results]

debug2: channel 0: rcvd eof

debug2: channel 0: output open -> drain

debug2: channel 0: obuf empty

debug2: channel 0: close_write

debug2: channel 0: output drain -> closed

debug1: client_input_channel_req: channel 0 rtype exit-status reply 0

debug2: channel 0: rcvd close


I would like to know how to fix server1 so that the connection isn't automatically closed so that my script can execute completely when including sudo commands.






ssh rhel sudo







share|improve this question















I have two servers running the same version of RedHat 6.4, however one of them behaves differently when I run remote sudo commands through SSH on it. On server1, the connection is automatically closed after a successful sudo command, but on server3, the connection is kept open.



Note that for these tests the sudo user had the NOPASSWD flag so no prompt is asked. As far as I know, all configurations on these servers are the same (they were cloned).



I tested using this:



ssh -vvv user@server1 << EOF

sudo ls -l /home/

ls -l /home/

pwd

EOF


If I run this on server1 I get a single file listing.



debug3: Wrote 32 bytes for a total of 1621

total 40

drwxr-xr-x.  5 user       user       4096 Apr 26  2013 user

debug1: client_input_channel_req: channel 0 rtype exit-status reply 0

debug2: channel 0: rcvd eof

debug2: channel 0: output open -> drain


Running without the sudo command on the same server I get my two file listing and the pwd result 



ssh -vvv user@server1 << EOF

ls -l /home/

ls -l /home/

pwd

EOF


Result:



debug3: Wrote 32 bytes for a total of 1605

total 40

drwxr-xr-x.  5 user       user       4096 Apr 26  2013 user

total 40

drwxr-xr-x.  5 user       user       4096 Apr 26  2013 user

/home/user

debug1: client_input_channel_req: channel 0 rtype exit-status reply 0

debug2: channel 0: rcvd eof

debug2: channel 0: output open -> drain


However, running the script with the sudo command on server3 I get the result of all 3 commands like the previous test. I compared the output of the ssh -vvv logs from both servers (1 and 3) and everything seems the same except for a debug line in a different order when the connection is closed (see client_input... line).



server1 (same with or without sudo)



[command results]

debug1: client_input_channel_req: channel 0 rtype exit-status reply 0

debug2: channel 0: rcvd eof

debug2: channel 0: output open -> drain

debug2: channel 0: obuf empty

debug2: channel 0: close_write

debug2: channel 0: output drain -> closed

debug2: channel 0: rcvd close


server3



[command results]

debug2: channel 0: rcvd eof

debug2: channel 0: output open -> drain

debug2: channel 0: obuf empty

debug2: channel 0: close_write

debug2: channel 0: output drain -> closed

debug1: client_input_channel_req: channel 0 rtype exit-status reply 0

debug2: channel 0: rcvd close


I would like to know how to fix server1 so that the connection isn't automatically closed so that my script can execute completely when including sudo commands.






ssh rhel sudo




ssh rhel sudo






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited yesterday









Rui F Ribeiro

38.7k1479128




38.7k1479128










asked yesterday









Bibz

1209




1209












  • I wonder if errexit is being set?
    – Jeff Schaller
    yesterday






  • 1




    also, compare the /etc/sudoers files (including /etc/sudoers.d/*), keeping an eye out for any requiretty or !requiretty differences. Perhaps server3 has been configured to allow sudo without requiring a tty, and server1 has not. One way to test would be to modify the server 1 command from ssh -vvv user@server1 ... to ssh -t -vvv user@server1.... The -t option will force the allocation of a tty. If sudo works doing that, then it's a tty requirement stuffing you up.
    – Tim Kennedy
    yesterday












  • errexit is off (command is successful anyway). requiretty is commented out in the sudoers file and sudoers.d directory is empty.
    – Bibz
    yesterday




















  • I wonder if errexit is being set?
    – Jeff Schaller
    yesterday






  • 1




    also, compare the /etc/sudoers files (including /etc/sudoers.d/*), keeping an eye out for any requiretty or !requiretty differences. Perhaps server3 has been configured to allow sudo without requiring a tty, and server1 has not. One way to test would be to modify the server 1 command from ssh -vvv user@server1 ... to ssh -t -vvv user@server1.... The -t option will force the allocation of a tty. If sudo works doing that, then it's a tty requirement stuffing you up.
    – Tim Kennedy
    yesterday












  • errexit is off (command is successful anyway). requiretty is commented out in the sudoers file and sudoers.d directory is empty.
    – Bibz
    yesterday


















I wonder if errexit is being set?
– Jeff Schaller
yesterday




I wonder if errexit is being set?
– Jeff Schaller
yesterday




1




1




also, compare the /etc/sudoers files (including /etc/sudoers.d/*), keeping an eye out for any requiretty or !requiretty differences. Perhaps server3 has been configured to allow sudo without requiring a tty, and server1 has not. One way to test would be to modify the server 1 command from ssh -vvv user@server1 ... to ssh -t -vvv user@server1.... The -t option will force the allocation of a tty. If sudo works doing that, then it's a tty requirement stuffing you up.
– Tim Kennedy
yesterday






also, compare the /etc/sudoers files (including /etc/sudoers.d/*), keeping an eye out for any requiretty or !requiretty differences. Perhaps server3 has been configured to allow sudo without requiring a tty, and server1 has not. One way to test would be to modify the server 1 command from ssh -vvv user@server1 ... to ssh -t -vvv user@server1.... The -t option will force the allocation of a tty. If sudo works doing that, then it's a tty requirement stuffing you up.
– Tim Kennedy
yesterday














errexit is off (command is successful anyway). requiretty is commented out in the sudoers file and sudoers.d directory is empty.
– Bibz
yesterday






errexit is off (command is successful anyway). requiretty is commented out in the sudoers file and sudoers.d directory is empty.
– Bibz
yesterday

















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