Troubleshooting SCS Access

If you are having problems accessing the ITS Statistics and Computation Service (SCS), here are some things you should check for and how to report problems. This page is kind of long, but you may as well read it over and try things because we're going to ask you to do the relevant stuff anyway.

FIRST: Check For Outages

Before doing anything else, check the ITS Service Status website. If there is an outage or an ongoing maintenance, it will be listed there.

If there is nothing there that looks like it affects the SCS services or the network between you and them, proceed with the items below.

Common Failures

If you are attempting to access the servers (especially if it is for the first time) and have problems, here are the most common causes.

  • AFS has not been set up for you. This is the most common cause of failure for first-time users. See Verify Your AFS and Kerberos Access for how to check your AFS account, and Setting Up Your AFS Access for how to set it up if not present.
  • Wrong service name. Make sure you have correctly used one of these names for the servers:
    • scs.dsc.umich.edu for the statistics servers;
    • login.itd.umich.edu for the login servers; or
    • sftp.itd.umich.edu for the sftp servers.

    Note that the old GPCC names are being removed, so if you're attempting to access name.gpcc.itd.umich.edu, try name.dsc.umich.edu instead. Note also that as we transition to the new login service, the the sftp will service is being merged with it. At some point in the future, we will retire the sftp name.

  • You can log in, but can't run GUI/Graphics applications. See the X11/Graphical Programs page for these issues.
  • You have been administratively blocked. If this is the case you will get a message when you attempt to log in saying there is some sort of problem with your U-M account and telling you who to contact about it. Note that if you were attempting to use the sftp service you might not see the message. Please try using ssh and log onto the scs or login services as named above.

Other Problems and Diagnoses

Your Access Fails Immediately

If your attempt to contact the server fails immediately (before you get a password prompt), please wait a few minutes and try again. If the problem persists, it is likely there is a network problem. Please call your local admin (if any), otherwise contact the ITS Service Center. If they see no problem, they will usually open a trouble ticket for you and pass it over to us.

Your Access Attempt Hangs Without A Password Prompt, Then Fails

If you are not prompted for a password, get no response for 10 to 60 seconds, and are then disconnected, it is highly likely there is a network problem. If the problem continues, contact the ITS Service Center saying that your attempts to access the SCS service never completes and your are disconnected after a while. and are immediately disconnected when trying to access the SCS service. Be sure to give them the time of the failure, the uniqname you are using, the name of the service you are trying to access, where you are coming from (on-campus vs. off-campus), your computer name or IP address if available, and any other symptoms or error messages.

Your Access Fails After Password Entered

  • If you get prompted for a password, enter it, and are disconnected immediately and you do not get a message about being administratively denied, please try the Kerberos and Mfile tests. If they fail, report the problem as described there. If they work, continue to the next test below.
  • If you get prompted for a password and are either disconnected after a pause or the connection simply hangs, note the length of time and continue as below.

If you have an account on some non-SCS system with AFS, try to access your account there. If you can, you may want to try a redot to reset your configuration files. Then try to connect to the SCS service again. If it succeed, great. If access still fails, or if you are unable or unwilling to try the redot solution, contact the ITS Service Center saying that you have successfully tested your AFS and Kerboros access with Mfile but are immediately disconnected when trying to access the SCS service. Let them know if you have or haven't tried the redot, and if you were able to access your AFS files through some other server. Be sure to also give them time of the failure, the uniqname you are using, the name of the service you are trying to access, where you are coming from (on-campus vs. off-campus), your computer name or IP address if available, and any other symptoms or error messages.

Tests and Possible Solutions

Verify Your AFS and Kerberos Accounts

To use the SCS servers, you need both a standard U-M account with your login name and password, and access to AFS. You can test both by trying to access AFS through Mfile, the web interface for AFS. Please try to log into Mfile. You should see a browser-based access to your AFS files. If the login fails saying you have no AFS account, follow the instructions below to setup your AFS account.

If the login to Mfile fails for any other reason, contact the ITS Service Center telling them you are unable to access AFS through Mfile. Be sure to give them the time of the failure, the uniqname you are using, where you are coming from (on-campus vs. off-campus), and any other symptoms or error messages.

Setting Up Your AFS Access

If this is the first time you've tried to access these servers, the most likely cause of failure is that your account has not yet been set up for use of AFS (sometimes called IFS). AFS is free to anyone with the standard University computing service package, but it is not set up automatically for new users. Here's how you can check if you have AFS access and how to request it if you don't have it.

In your web browser, go to Mfile, the web interface to AFS. Attempt to log in. If it fails, it is almost certian that AFS has not yet been set up for your use. Go back to the Mfile page again and click on the AFS Self-Provisioning Tool link. Fill out the form there.

If that fails, contact the ITS Service Center stating that AFS Self-Provisioning failed. Be sure to give them the time of the failure, the uniqname you are using, where you are coming from (on-campus vs. off-campus), your computer name or IP address if available, and any other symptoms or error messages.

It can take a while for newly set-up AFS accounts to be active on all the machines that use AFS. So once your account seems to have been set up, wait at least 20 minutes for all the machines to pick up the account data.

After the 20 minutes has passed, verify your AFS setup.

Once you've verified that your account has been set up, please try again to log onto the server.

If you have verified your AFS setup and still cannot access the servers, contact the ITS Service Center telling them you cannot contact the SCS service. Be sure to give them the time of the failure, the uniqname you are using, the name of the service you are trying to access, where you are coming from (on-campus vs. off-campus), your computer name or IP address if available, and any other symptoms or error messages.

Resetting Your Account Initialization Files

If you are able to access your AFS account by logging on to some other AFS-based system (other than the SCS servers), it is likely there is something in your account initialization files (“dotfiles”) that conflicts with the setups on the SCS servers. If so, please try reverting your account setups to the defaults. On many systems, this can be done with the redot command. If there is no redot command on that machine, please check with the administrator for that system on how to reset the dotfiles.

Note that the SCS-supplied redot command makes backup copies of the dotfiles it resets, but there is no guarantee that other system providers' versions will do the same. Check with the administrator for that system to see what theirs does or make backup copies of all your dotfiles.

If there is no redot command on that system or if you perform a reset and it fails, contact the ITS Service Center saying your can access AFS from some other service, but when trying to use the SCS service you get prompted for a password to the SCS service and are immediately dropped. Be sure to give them the time of the failure, the uniqname you are using, the name of the service you are trying to access, where you are coming from (on-campus vs. off-campus), your computer name or IP address if available, and any other symptoms or error messages that come up.