RSA stopped supporting FTP connections with iSeries but failed to update their documentation with the steps for SFTP.
This is a document from IBM which describes some of the steps for the key exchange: http://www-01.ibm.com/support/docview.wss?uid=nas8N1012710
I have been making a couple of tests to understand what is going on.
sftp is the standard sftp user on the Collector
ISERIESFTP is the legacy FTP user on the Collector that was previously used for iSeries and has different permissions than sftp user.
The initial challenge was that iSeries does not support sftp client with password authentication. So the “sftp collector-ip” command for caching the keys would not work.
IBM suggests to use the command bellow for the key caching
ssh -T serveruid@somehost
These are the steps performed on iSeries side:
*****
ssh-keygen -t rsa -N ""
Generating public/private rsa key pair.
Enter file in which to save the key (/home/CAFGSECADM/.ssh/id_rsa):
Created directory '/home/CAFGSECADM/.ssh'.
Your identification has been saved in /home/CAFGSECADM/.ssh/id_rsa.
Your public key has been saved in /home/CAFGSECADM/.ssh/id_rsa.pub.
The key fingerprint is:
2d:87:7c:55:45:1c:a4:53:0d:60:ea:76:40:b3:c9:3e cafgsecadm@blabla.123.co.uk
*****
Key is on both of these directories on the target (VLC):
/home/upload/.ssh/authorized_keys
/upload/.ssh/authorized_keys
*****
ssh -t ISERIESFTP@10.160.x.x
ISERIESFTP@10.160.x.x's password: tcgetattr: Invalid argument
Last login: Thu Oct 19 15:29:42 2017 from 10.160.x.y
[ISERIESFTP@Collector1 ~]$
*****
ssh -T sftp@10.160.x.x
This service allows sftp connections only.
*****
$
sftp sftp@10.160.x.x
Connected to 10.160.x.x ...
sftp>
So at this stage you can see that we are getting an sftp prompt on iSeries without been prompted for a password (which means that public-key authentication works).
Then we try to run the script again with user sftp that we now know it should work:
OpenSSH_6.6, OpenSSL 1.0.1p 9 Jul 2015
debug1: Reading configuration data /QOpenSys/QIBM/ProdData/SC1/OpenSSH/openssh-4.7p1/etc/ssh_config
debug1: Connecting to 10.160.x.x [10.160.x.x] port 22.
debug1: Connection established.
debug1: identity file /home/CAFGSECADM/.ssh/id_rsa type 1
debug1: identity file /home/CAFGSECADM/.ssh/id_rsa-cert type -1
debug1: identity file /home/CAFGSECADM/.ssh/id_dsa type -1
debug1: identity file /home/CAFGSECADM/.ssh/id_dsa-cert type -1
debug1: identity file /home/CAFGSECADM/.ssh/id_ecdsa type -1
debug1: identity file /home/CAFGSECADM/.ssh/id_ecdsa-cert type -1
debug1: identity file /home/CAFGSECADM/.ssh/id_ed25519 type -1
debug1: identity file /home/CAFGSECADM/.ssh/id_ed25519-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_6.6
debug1: Remote protocol version 2.0, remote software version OpenSSH_5.3
debug1: match: OpenSSH_5.3 pat OpenSSH_5* compat 0x0c000000
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client aes128-ctr hmac-sha1 none
debug1: kex: client->server aes128-ctr hmac-sha1 none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<7680<8192) sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug1: Server host key: RSA 52:9a:14:f3:3a:05:eb:a3:3c:1d:10:fe:b6:13:a7:58
debug1: Host '10.160.x.x is known and matches the RSA host key.
debug1: Found key in /home/CAFGSECADM/.ssh/known_hosts:1
debug1: ssh_rsa_verify: signature correct
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: Roaming not allowed by server
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic,password
debug1: Next authentication method: publickey
debug1: Offering RSA public key: /home/CAFGSECADM/.ssh/id_rsa
debug1: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic,password
debug1: Trying private key: /home/CAFGSECADM/.ssh/id_dsa
debug1: Trying private key: /home/CAFGSECADM/.ssh/id_ecdsa
debug1: Trying private key: /home/CAFGSECADM/.ssh/id_ed25519
debug1: No more authentication methods to try.
Permission denied (publickey,gssapi-keyex,gssapi-with-mic,password).
Connection closed
I understand that the key is read and accepted but then fails to be used. What could be the reason? Could it be some
Any help would be appreciated
Thanks
Marinos
