From Bugzilla Helper: User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.1) Gecko/20020827 Description of problem: running sshd on a redhat 8.0 and connecting from redhat 7.3, i get no response. Version-Release number of selected component (if applicable): How reproducible: Always Steps to Reproduce: 1.environment (see additional information) 2.ssh <redhat8.0 box> Actual Results: the ssh hangs and gives no feedback Expected Results: i should get the password: prompt Additional info: strace of the sshd on the 8.0 box: # strace -fp 20490 select(4, [3], NULL, NULL, NULL) = 1 (in [3]) accept(3, {sin_family=AF_INET, sin_port=htons(48740), sin_addr=inet_addr("193.77.112.21")}}, [16]) = 4 fcntl(4, F_SETFL, O_RDONLY) = 0 pipe([5, 6]) = 0 fork() = 20497 [pid 20490] --- SIGCHLD (Child exited) --- [pid 20490] wait4(-1, 0x7ffff140, WNOHANG, NULL) = -1 ECHILD (No child processes) [pid 20490] rt_sigaction(SIGCHLD, {0x804cd20, [CHLD], SA_RESTORER|SA_RESTART, 0x2ac7ec88}, {0x804cd20, [CHLD], SA_RESTORER|SA_RESTART, 0x2ac7ec88}, 8) = 0 [pid 20490] sigreturn() = ? (mask now []) [pid 20490] close(6) = 0 [pid 20490] rt_sigaction(SIGALRM, {0x804ce80, [ALRM], SA_RESTORER|SA_RESTART, 0x2ac7ec88}, {SIG_DFL}, 8) = 0 [pid 20490] alarm(3600) = 0 [pid 20490] getpid() = 20490 [pid 20490] getpid() = 20490 [pid 20490] close(4) = 0 [pid 20490] select(6, [3 5], NULL, NULL, NULL <unfinished ...> as can be seen, the child process immediately exits for unknown reason. ssh -vvv output on the 7.3 box: $ ssh -vvv root.8.63 OpenSSH_3.1p1, SSH protocols 1.5/2.0, OpenSSL 0x0090600f debug1: Reading configuration data /home/me/.ssh/config debug1: Reading configuration data /etc/ssh/ssh_config debug1: Applying options for * debug1: Rhosts Authentication disabled, originating port will not be trusted. debug1: restore_uid debug1: ssh_connect: getuid 8043 geteuid 0 anon 1 debug1: Connecting to 172.16.8.63 [172.16.8.63] port 22. debug1: temporarily_use_uid: 8043/8000 (e=0) debug1: restore_uid debug1: temporarily_use_uid: 8043/8000 (e=0) debug1: restore_uid debug1: Connection established. debug1: read PEM private key done: type DSA debug1: read PEM private key done: type RSA debug1: identity file /home/me/.ssh/identity type 0 debug3: Not a RSA1 key file /home/me/.ssh/id_rsa. debug2: key_type_from_name: unknown key type '-----BEGIN' debug3: key_read: no key found debug3: key_read: no space debug3: key_read: no space debug3: key_read: no space debug3: key_read: no space debug3: key_read: no space debug3: key_read: no space debug3: key_read: no space debug3: key_read: no space debug3: key_read: no space debug3: key_read: no space debug3: key_read: no space debug3: key_read: no space debug3: key_read: no space debug2: key_type_from_name: unknown key type '-----END' debug3: key_read: no key found debug1: identity file /home/me/.ssh/id_rsa type 1 debug3: Not a RSA1 key file /home/me/.ssh/id_dsa. debug2: key_type_from_name: unknown key type '-----BEGIN' debug3: key_read: no key found debug3: key_read: no space debug3: key_read: no space debug3: key_read: no space debug3: key_read: no space debug3: key_read: no space debug3: key_read: no space debug3: key_read: no space debug3: key_read: no space debug3: key_read: no space debug3: key_read: no space debug2: key_type_from_name: unknown key type '-----END' debug3: key_read: no key found debug1: identity file /home/me/.ssh/id_dsa type 2 debug1: Remote protocol version 1.99, remote software version OpenSSH_3.1p1 debug1: match: OpenSSH_3.1p1 pat OpenSSH* Enabling compatibility mode for protocol 2.0 debug1: Local version string SSH-2.0-OpenSSH_3.1p1 debug1: SSH2_MSG_KEXINIT sent debug1: SSH2_MSG_KEXINIT received debug2: kex_parse_kexinit: diffie-hellman-group-exchange-sha1,diffie-hellman-group1-sha1 debug2: kex_parse_kexinit: ssh-rsa,ssh-dss debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,aes192-cbc,aes256-cbc debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,aes192-cbc,aes256-cbc debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-ripemd160,hmac-ripemd160,hmac-sha1-96,hmac-md5-96 debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-ripemd160,hmac-ripemd160,hmac-sha1-96,hmac-md5-96 debug2: kex_parse_kexinit: none debug2: kex_parse_kexinit: none debug2: kex_parse_kexinit: debug2: kex_parse_kexinit: debug2: kex_parse_kexinit: first_kex_follows 0 debug2: kex_parse_kexinit: reserved 0 debug2: kex_parse_kexinit: diffie-hellman-group-exchange-sha1,diffie-hellman-group1-sha1 debug2: kex_parse_kexinit: ssh-rsa,ssh-dss debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,aes192-cbc,aes256-cbc debug2: kex_parse_kexinit: aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,aes192-cbc,aes256-cbc debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-ripemd160,hmac-ripemd160,hmac-sha1-96,hmac-md5-96 debug2: kex_parse_kexinit: hmac-md5,hmac-sha1,hmac-ripemd160,hmac-ripemd160,hmac-sha1-96,hmac-md5-96 debug2: kex_parse_kexinit: none,zlib debug2: kex_parse_kexinit: none,zlib debug2: kex_parse_kexinit: debug2: kex_parse_kexinit: debug2: kex_parse_kexinit: first_kex_follows 0 debug2: kex_parse_kexinit: reserved 0 debug2: mac_init: found hmac-md5 debug1: kex: server->client aes128-cbc hmac-md5 none debug2: mac_init: found hmac-md5 debug1: kex: client->server aes128-cbc hmac-md5 none debug1: SSH2_MSG_KEX_DH_GEX_REQUEST sent debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP debug1: dh_gen_key: priv key bits set: 121/256 debug1: bits set: 1593/3191 debug1: SSH2_MSG_KEX_DH_GEX_INIT sent debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY debug3: check_host_in_hostfile: filename /home/me/.ssh/known_hosts2 debug3: key_read: type mismatch debug3: check_host_in_hostfile: filename /etc/ssh/ssh_known_hosts2 debug3: check_host_in_hostfile: filename /home/me/.ssh/known_hosts debug2: key_type_from_name: unknown key type '1024' debug3: key_read: no key found debug3: check_host_in_hostfile: filename /etc/ssh/ssh_known_hosts Warning: Permanently added '172.16.8.63' (RSA) to the list of known hosts. debug1: bits set: 1594/3191 debug1: ssh_rsa_verify: signature correct debug1: kex_derive_keys debug1: newkeys: mode 1 debug1: SSH2_MSG_NEWKEYS sent debug1: waiting for SSH2_MSG_NEWKEYS debug1: newkeys: mode 0 debug1: SSH2_MSG_NEWKEYS received debug1: done: ssh_kex2. debug1: send SSH2_MSG_SERVICE_REQUEST debug1: service_accept: ssh-userauth debug1: got SSH2_MSG_SERVICE_ACCEPT debug1: authentications that can continue: publickey,password,keyboard-interactive debug3: start over, passed a different list publickey,password,keyboard-interactive debug3: preferred publickey,keyboard-interactive,password debug3: authmethod_lookup publickey debug3: remaining preferred: keyboard-interactive,password debug3: authmethod_is_enabled publickey debug1: next auth method to try is publickey debug1: try pubkey: /home/me/.ssh/id_rsa debug3: send_pubkey_test debug2: we sent a publickey packet, wait for reply debug1: authentications that can continue: publickey,password,keyboard-interactive debug1: try pubkey: /home/me/.ssh/id_dsa debug3: send_pubkey_test debug2: we sent a publickey packet, wait for reply debug1: authentications that can continue: publickey,password,keyboard-interactive debug2: we did not send a packet, disable method debug3: authmethod_lookup keyboard-interactive debug3: remaining preferred: password debug3: authmethod_is_enabled keyboard-interactive debug1: next auth method to try is keyboard-interactive debug2: userauth_kbdint debug2: we sent a keyboard-interactive packet, wait for reply debug1: authentications that can continue: publickey,password,keyboard-interactive debug3: userauth_kbdint: disable: no info_req_seen debug2: we did not send a packet, disable method debug3: authmethod_lookup password debug3: remaining preferred: debug3: authmethod_is_enabled password debug1: next auth method to try is password root.8.63's password: debug1: packet_send2: adding 64 (len 57 padlen 7 extra_pad 64) debug2: we sent a password packet, wait for reply debug1: ssh-userauth2 successful: method password debug3: clear hostkey 0 debug3: clear hostkey 1 debug3: clear hostkey 2 debug1: channel 0: new [client-session] debug3: ssh_session2_open: channel_new: 0 debug1: send channel open 0 debug1: Entering interactive session. debug2: callback start debug1: ssh_session2_setup: id 0 debug1: channel request 0: pty-req debug3: tty_make_modes: ospeed 38400 debug3: tty_make_modes: ispeed 38400 debug3: tty_make_modes: 1 3 debug3: tty_make_modes: 2 28 debug3: tty_make_modes: 3 127 debug3: tty_make_modes: 4 21 debug3: tty_make_modes: 5 4 debug3: tty_make_modes: 6 255 debug3: tty_make_modes: 7 255 debug3: tty_make_modes: 8 17 Connection to 172.16.8.63 closed. for the 8.0 box: it's one of the famous 440gx machines that refuse to run properly with any 2.4 kernel (aic7xxx irq routing & co fun). in this case i was forced to use latest kernel for the redhat 6.2 (2.2.19-6.2.16). could this have to do something with this ssh issue?
I downgraded openssh packages on the 8.0 box to those from 7.3 updates (3.1p1-6) and ssh started to work as expected.
Neither 7.3 nor 8.0 are supported anymore.