The National Institute for Computational Sciences

Access and Login - SIP

There are two login nodes sip-login1 and sip-login2. sip-login1 is for use by UTK sponsored researchers and sip-login2 is for use by UTHSC sponsored researchers. To gain access to SIP resources three things are needed: access to a project with an account on the SIP (see Projects and Accounts below), access to the SIP bastion host, and a UT NetID and password along with access to use one of the supported multi-factor authentications (MFA) capabilities.

Here is the important node information for access to the SIP:

ACF SIP Bastion Host NameAuthentication SupportedFile System Access UTK/UTHSC Netid + DuoNone
ACF Login Host Name for UTKAuthentication SupportedFile System Access,
UTK netid + DuoHome,
ACF Login Host Name for UTHSCAuthentication SupportedFile System Access,
UTHSC netid + DuoHome,

Projects and Accounts

UTK and UTHSC researchers must create an account on the ACF Open side as the first step to getting a ACF SIP account by claiming an ACF Open account using one's UT NetID at this ACF User Account form. Once you have created an ACF Open account one can request a SIP project by going back to the ACF User Account form, authenticating, and then click on the "Request a new project on the SIP enclave" and fill out all the requested information. This will include attaching a project Secure Enclave Research Infrastructure intake form document. The form is linked to on the page where it is required to be attached. The ACF is working with UTK OIT to have remote access to the ACF SIP be through the Secure Enclave Citrix environment. Once you have an ACF SIP account you will also have Secure Enclave Citrix access to In the mean time, until the Secure Enclave Citrix environment is available users would use SSH to login to the the SIP Bastion host to then SSH to the appropriate SIP login node.

Bastion Host Access

Once you obtain a SIP project you will be added to a SIP bastion host. This will be done for you as part of the process to create a SIP project. The SIP bastion hosts are created to provide controlled access from remote locations to the SIP resources. To gain access to the SIP login nodes one has to login to a SIP bastion host then login to the SIP login node. This allows more open access to SIP resources from computers on the UTK and UTHSC networks without having to manage individual SIP firewall rules for all systems that want to access and prevents data transfer from unauthorized systems. Access to the bastion host will be allowed from the UTHSC and UTK managed networks including the VPNs. By allowing the VPNs this allows users to use portable devices on networks outside of UTK and UTHSC, connect to one's campus VPN to get on the UTK or UTHSC network, and then access SIP resources through the SIP bastion hosts.

About SSH

UNIX-based operating systems generally have an SSH client built in and Windows users may obtain free clients online, such as PuTTY.

Any SSH client used to log into resources should:

  • Support the SSH-2 protocol (supported by all modern SSH clients). Several security vulnerabilities exist in the SSH-1 protocol, therefore, access using a version 1 client is not allowed.
  • Support the encryption algorithms that our Secure Shell server version 5.8 supports.
  • Allow keyboard-interactive authentication to access NICS systems. For UNIX-based SSH clients, the following line should be in either the default ssh_config file or your  $HOME/.ssh/config file:
    PreferredAuthentications keyboard-interactive,password
    The line may also contain other authentication methods, so long as keyboard-interactive is included. For recent versions of SecureCRT or PuTTY, the setting can be made through the SSH connection properties menu.

Other Login Issues

Inactive accounts

Accounts that are not used for a period of three consecutive months are disabled. If you believe your account has been disabled for inactivity please submit a request to

RSA Key Fingerprints

Occasionally, you may receive an error message upon logging in to a system such as the following:

Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that the OTP host key has just been changed.

This can be a result of normal system maintenance that changes an RSA public key or could be an actual security incident. If these fingerprints do not match what your SSH/SCP/SFTP client shows you, do not continue authentication; instead, contact

X11 and Other Port Forwarding

X11 forwarding is not allowed currently through the SIP bastion hosts. Also, no other port forwarding is allowed through the bastion hosts.

Changing Default Shell

You may change your default shell, by logging into the NICS User portal. After logging in to the portal, you may change your shell in the 'Login Information' section.