Nevis1 Mail Forwarding On 16:00 Mon 26-Aug-2002, I plan to change the sendmail configuration on nevis1. The machine will no longer send mail on its own, but forward it to the main mail server, franklin, for further processing. This web page discusses:
  • why this is being done,
  • the answers to a couple of frequently-asked questions,
  • how this will change the "From:" address on the e-mail you send,
  • and how having a different account on the Linux cluster might affect you.
  • As part of the transition in mail services at Nevis, as of 26-Aug-2002 I plan to change the mailer configuration on nevis1. The sendmail program on nevis1 will act as a "null client": it will not directly send nor receive any mail on its own. All the mail processing will be forwarded to the main mail server, franklin.

    By the way, this is exactly the same sendmail configuration that's used on all the machines in the Nevis Linux cluster except for franklin itself.

    This change is part of the transition of mail and other network services from nevis1 to the Linux cluster. The first part of the transition, putting the new mail server into use, took place in May 2002.


    Why this is being done

    Ever since franklin became the main mail server at Nevis, all the mail that is sent to Nevis flows through it. Any mail sent from (or to) any machine in the Nevis Linux cluster is also routed via franklin. There is one exception: nevis1, which has been running a full-fledged mail server on its own.

    This has made mailer configuration more difficult. If you send e-mail to jsmith@nevis.columbia.edu from anywhere else on the planet, it reach its appropriate destination. But if you send e-mail to jsmith@nevis.columbia.edu from nevis1, it won't get there unless Jane Smith maintains a separate account on nevis1. And if Jane Smith has a different home directory defined on nevis1 versus the Linux cluster, then she has to edit ~/.forward files on two different machines to make sure her mail is forwarded properly.

    Also, the mail program on nevis1 is a very old version with several security holes; it's also more difficult to configure. It's time to retire it, and allow the more secure franklin to handle the mail.


    Frequently Asked Questions

    Is mail being turned off on nevis1?

    No, it's not. It would be more accurate to say that mail processing is being turned off on nevis1. After this change, all Nevis mail will be forwarded and processed through franklin.

    What about reading my mail via IMAP or POP?

    The way you read your mail will not change at all. Sendmail, the program that transfers mail between computers, is completely different from the services (imapd and pop3d) that allow you to read your mail. You will still be able to able to use nevis1 to read your mail.

    Eventually I plan to migrate the IMAP and POP services solely to franklin, but that change is months in the future.

    What about mail that's sent to old-style mail addresses like jsmith@nevis1.columbia.edu?

    That was already taken care of at the time that franklin became the main mail server. Mail sent to addresses of the following form will reach you without any problems:

    jsmith@nevis.columbia.edu
    jsmith@nevis1.nevis.columbia.edu
    jsmith@nevis1.columbia.edu

    Are any changes required to the mail programs we use?

    No. If you feel like making changes to prepare for future changes in mail services:

    The following two sections describe the only ways you might be affected by this change in mail processing on nevis1.


    Your "From" header

    When franklin processes your mail, it will convert an address in the "sender" or "From" header lines from <account>@<machine>.nevis.columbia.edu to <account>@nevis.columbia.edu. This "canonicalization" of the mail addresses will make life easier for us in the future; in particular, if we have to switch mail servers again, you won't have to keep changing your e-mail address.

    However, this was not done on nevis1; all mail sent from that machine has a "From" address of <account>@nevis1.nevis.columbia.edu. This will pose a problem if you send mail to a service that restricts access based on the "From" part of your e-mail header. Many list-servers (in particular, those at BNL) will reject mail from jsmith@nevis.columbia.edu if only jsmith@nevis1.nevis.columbia.edu is on their list of acceptable users.

    If you are on such a group mailing list, you'll have to inform the maintainers of the list of upcoming change in your e-mail address.


    Multiple accounts

    On the page that described the switch to the new mail server, I went into detail about the consequences of having a different home directory on your Linux account.

    After the change in mail processing on nevis1, your home directory as seen by nevis1 will become irrelevant to how your mail is received; your home directory as defined on the Linux cluster will define how your mail is processed.

    Here are the cases to be considered:

    1. If you never had an account on the Linux cluster, then do nothing. I've already defined your Linux cluster home directory to be the same as your home directory on nevis1.

    2. If you have an account on the Linux cluster, but you never use it, you may to consider having me change the definition of your Linux cluster home directory to point to your area on nevis1. Otherwise, as I previously described, you'll have to log on to the cluster whenever you want to make changes to your ~/.forward file.

    3. If you are active on both the Linux cluster and on nevis1, you only have to maintain your ~/.forward file on the cluster. You may want to consider reading your mail on the cluster instead of on nevis1, but there's no pressing need to change.

    4. If you use the Linux cluster exclusively, and only use nevis1 to check your mail, you don't have to log in to nevis1 anymore.

    For the last two cases, you may want to copy your mail directories on nevis1 to your home directory on the Linux cluster. The following commands, executed on the cluster, will probably do what you want:

    cd scp -r nevis1:~/mail .

    If you have any difficulty, please feel free to contact me to help you move your mail files to the Linux cluster.


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