Summary:
I'm trying to connect from my laptop to my Desktop to transfer files using
sftp username@localIP but it gives me connection timeout
Case:
Both machines are using Linux and connected to the same router:
machine 1: Desktop connected to internet using a USB tethering phone connected to the same router as the second machine
machine 2: Laptop connected to internet using wireless
IP for each device using hostname -I:
Desktop: 192.168.42.130
Laptop: 192.168.1.2
Issue:
I can connect from Desktop to Laptop but not vice versa. I used it a lot from Desktop->Laptop but each time i try to connect from Laptop->Desktop this happens:
(takes 2 minutes)
(ssh: connect to host 192.168.42.130 port 22: Connection timed out
connection closed)
1) tried to set GSPAuthentication to no
2) tried to set UseDNS to no
3) restarted the service
But to no avail
Update:
Below are results after scanning for the issue (@A.B suggested that the problem is due to NAT)
Note: Len short for Lenovo (i.e.laptop)
Note: There are only two Linux machines on the router
Note: I have no wire so i use on my desktop a cell phone to connect to internet (using USB tethering)
1) connecting from Laptop->Desktop:
omar@omar-Len:~/Desktop$ sftp [email protected] ssh: connect to host 192.168.1.8 port 22: Connection refused Connection closed
2) Checking Desktop Address (before connection):
omar@omar-LDesktop:~$ ip -brief address
lo UNKNOWN 127.0.0.1/8 ::1/128
enp0s25 DOWN
enp0s29f7u2 UNKNOWN 192.168.42.130/24 fe80::69ce:4a20:5a7e:433c/64
3) on the laptop to check open connections (before connecting the two machines):
omar@omar-Len:~/Desktop$ netstat -tn | egrep -w 22
omar@omar-Len:~/Desktop$
(connected the two machines from pc->laptop)
4) checking open connection:
(Desktop)
omar@omar-LDesktop:~$ netstat -tn | egrep -w 22
tcp 0 0 192.168.42.130:44644 192.168.1.2:22 ESTABLISHED
(Laptop)
omar@omar-Len:~/Desktop$ netstat -tn | egrep -w 22
tcp 0 0 192.168.1.2:22 192.168.1.8:44644 ESTABLISHED
(Desktop)
omar@omar-LDesktop:~$ ps -ef | grep [s]shd
root 30538 1 0 19:07 ? 00:00:00 /usr/sbin/sshd -D
update 2: (I though of connecting the 2 machines through internet to avoid the NAT, so here is my trial)
I used sftp -vvv <publicIP>@<LocalIP>
to connect from Desktop->Laptop and it asked me for the password and when i entered it it returned back "Permission Denied" although it connects normal if i do not use the <publicIP>
Here is the debugging log from the Desktop: (note, i changed my <publicIP>)
sftp -vvv <publicIP>@omar-@[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 "192.168.1.2" port 22
debug2: ssh_connect_direct: needpriv 0
debug1: Connecting to 192.168.1.2 [192.168.1.2] port 22.
debug1: Connection established.
debug1: key_load_public: No such file or directory
debug1: identity file /home/omar/.ssh/id_rsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/omar/.ssh/id_rsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/omar/.ssh/id_dsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/omar/.ssh/id_dsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/omar/.ssh/id_ecdsa type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/omar/.ssh/id_ecdsa-cert type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/omar/.ssh/id_ed25519 type -1
debug1: key_load_public: No such file or directory
debug1: identity file /home/omar/.ssh/id_ed25519-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_7.6p1 Ubuntu-4ubuntu0.3
debug1: match: OpenSSH_7.6p1 Ubuntu-4ubuntu0.3 pat OpenSSH* compat 0x04000000
debug2: fd 3 setting O_NONBLOCK
debug1: Authenticating to 192.168.1.2:22 as '<publicIP>@omar-@omar-Len'
debug3: hostkeys_foreach: reading file "/home/omar/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /home/omar/.ssh/known_hosts:1
debug3: load_hostkeys: loaded 1 keys from 192.168.1.2
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,diffie-hellman-group14-sha1
debug2: host key algorithms: ssh-rsa,rsa-sha2-512,rsa-sha2-256,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: <hostKey>
SHA256:<SHA256>
debug3: hostkeys_foreach: reading file "/home/omar/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /home/omar/.ssh/known_hosts:1
debug3: load_hostkeys: loaded 1 keys from 192.168.1.2
debug1: Host '192.168.1.2' is known and matches the ECDSA host key.
debug1: Found key in /home/omar/.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/omar/.ssh/id_rsa ((nil))
debug2: key: /home/omar/.ssh/id_dsa ((nil))
debug2: key: /home/omar/.ssh/id_ecdsa ((nil))
debug2: key: /home/omar/.ssh/id_ed25519 ((nil))
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,ssh-rsa,rsa-sha2-256,rsa-sha2-512,ssh-dss,ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521>
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: Trying private key: /home/omar/.ssh/id_rsa
debug3: no such identity: /home/omar/.ssh/id_rsa: No such file or directory
debug1: Trying private key: /home/omar/.ssh/id_dsa
debug3: no such identity: /home/omar/.ssh/id_dsa: No such file or directory
debug1: Trying private key: /home/omar/.ssh/id_ecdsa
debug3: no such identity: /home/omar/.ssh/id_ecdsa: No such file or directory
debug1: Trying private key: /home/omar/.ssh/id_ed25519
debug3: no such identity: /home/omar/.ssh/id_ed25519: No such file or directory
debug2: we did not send a packet, disable method
debug3: authmethod_lookup password
debug3: remaining preferred: ,password
debug3: authmethod_is_enabled password
debug1: Next authentication method: password
<publicIP>@omar-@[email protected]'s password:
debug3: send packet: type 50
debug2: we sent a password packet, wait for reply
debug3: receive packet: type 51
debug1: Authentications that can continue: publickey,password
Permission denied, please try again.
This is the debugging from the Laptop:
May 4 14:59:39 omar-Len sshd[10133]: Invalid user <publicIP>@omar-@omar-Len from 192.168.1.8 port 56890
May 4 14:59:44 omar-Len sshd[10133]: pam_unix(sshd:auth): check pass; user unknown
May 4 14:59:44 omar-Len sshd[10133]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=192.168.1.8
May 4 14:59:47 omar-Len sshd[10133]: Failed password for invalid user <publicIP>@omar-@omar-Len from 192.168.1.8 port 56890 ssh2
May 4 14:59:49 omar-Len sshd[10133]: Connection closed by invalid user <publicIP>@omar-@omar-Len 192.168.1.8 port 56890 [preauth]
May 4 15:03:50 omar-Len sudo: omar : TTY=pts/0 ; PWD=/home/omar/Desktop ; USER=root ; COMMAND=/bin/nano //var/log/auth.log
May 4 15:03:50 omar-Len sudo: pam_unix(sudo:session): session opened for user root by (uid=0)
May 4 15:04:12 omar-Len sudo: pam_unix(sudo:session): session closed for user root
ss -tn sport = :22and both showed the same resutstate Recv-Q Send-Q Local Ddress:Port Peer Address:Portonly, no number or anything else