Tuesday, February 13, 2007

SSMTP/Getmail how-to part II

Back to Part I

It should've taken like two minutes to install or so. The getmail program is very nice and it follows the concept of do one ting and do it well + allows for a great level of modularity. We can use it with a number of protocols and other softwares like procmail, spamasassion, clamav e.t.c.

Setting up getmail is very easy and theres great documentation so far I've been very happy with it. Lets go to our home directory, we do *not* want to be the root user for this.

I'm gong to use a console because thats how i like it, so I'll short how to do it via that way. If you want to use a GUI app like Konqueror to do it be my guest, you should be able to easy enough.

Make a directory your home directory called .getmail and set the permissions so that only you have access.

mkdir -m 0700 ~/.getmail That ammounts to the owner having read, write, and execute but no one else but the root user being able to enter the directory. Lets cd over to our ~/.getmail folder and create a rc file. By default getmail reads the ${HOME}/.getmail/getmailrc file but we can create multiple rc files and have getmail use the one we choose.

getmail -rRCFILENAME

if its not in our .getmail/ folder we need to supply the path to the rc file, if its in .getmail we can skip it.

The syntax of the file reminds me alot of .ini files on Win32, to be perfectly honest the getmailrc file syntax is the easist I've seen. Heres a copy of one of the RC files I use complete with anotations of what the ooptions do. After this I'll go into more detail about the options to help you get a owrking rc file.

[retriever]
# This file is getmailrc-sas which is for checking my @sasclan.org account
type = SimplePOP3SSLRetriever
server = mail.host.tld
username = my_emailaddr@sasclan.org
password = My_Password

[destination]

# This destination is just for my e-mail not the systems local mboxes.
type = Maildir 
path = ~/Mail/
user = rstf
filemode = 0600

[options]
# Note that '0' means disable for all integar values.

# (int) 0-warn/err only, 1-retriv/delete only, 2-every thing
verbose = 1
# (bool) true = fetch all, false = only what getmail has not seen before
read_all = true
# (bool) true = delete messages after downloading, will override delete_after
delete = true
# (int) delete messages from server after int days
#delete_after = 1
# (int) max server reported message *total* size to download per session
max_bytes_per_session = 0
# (int) do not retreve messsages larger then this number of bytes
max_message_size = 0
# (int) max number of messages to process
max_messages_per_session = 0
# (bool) adds Delivered-To: header field to the message.
delivered_to = true
# (bool) add received: header field to the message
received = true
# (str) log to file
#message_log
# (bool) use system logger
message_log_syslog = false

as a reminder so I wouldn't have to check the documentation in /usr/local/share/doc/getmail/ or online. I put comment notes in the file briefing discribing what each option does and the type of setting, namely bool (i.e. true/false), int(eger) i.e. 0 1 or 435 e.t.c., or str(ing) likethis. Basically you need to have a [retriever] and a [destination] section. Under retriever we tell getmail what type of protocol to use, taken from the documentation heres the options.


  • SimplePOP3Retriever
    — for single-user POP3 mail accounts.

  • BrokenUIDLPOP3Retriever
    — for broken POP3 servers that do not support the
    UIDL
    command, or which do not uniquely identify messages; this provides basic
    support for single-user POP3 mail accounts on such servers.

  • SimpleIMAPRetriever
    — for single-user IMAP mail accounts.

  • SimplePOP3SSLRetriever
    — same as SimplePOP3Retriever, but uses SSL encryption.

  • BrokenUIDLPOP3SSLRetriever
    — same as BrokenUIDLPOP3Retriever, but uses SSL encryption.

  • SimpleIMAPSSLRetriever
    — same as SimpleIMAPRetriever, but uses SSL encryption.

  • MultidropPOP3Retriever
    — for domain mailbox (multidrop) POP3 mail accounts.

  • MultidropPOP3SSLRetriever
    — same as MultidropPOP3Retriever, but uses SSL encryption.

  • MultidropSDPSRetriever
    — for domain mailbox
    SDPS mail accounts,
    as provided by the UK ISP Demon.

  • MultidropIMAPRetriever
    — for domain mailbox (multidrop) IMAP mail accounts.

  • MultidropIMAPSSLRetriever
    — same as MultidropIMAPRetriever, but uses SSL encryption.

Odds are if you don't know what you need, its probably SimplePOP3Retriever. If you've ever set up a mail client before you should know it, your ISP or webhost should be able to tell you as well. Next we gotta tell getmail what server to fetch mail off of with the server option. If your ISP is some thing like charter, its probably mail.charter.net. I don't have charter but all the mail servers I've seen have been mail.ispname.topleveldomain lol.

We need to set the username and password so the server knows its us and which mailbox we want. Other wise it will tell us to go 'eff off.

Now we need to tell getmail what to do with our mail once it checks the incoming mail server. This is what the destination section is for. You basically have two big options here, Maildir or MBox. I've always used mboxrd since thats what Mozilla Mail&Newsgroups, Mozilla Thunderbird, and Seamonkey Mail&Newsgroups used. Plus the systems local mailboxes are mbox format as well. Theres various 'variations' of mbox and probably maildir but compatible enough for our needs I'd say. Other options for 'type' allow us to use an

External Message Delivery Agent (MDA) like procmail.
Mutilple Destinations, using multiple maildir/mbox/externMDAs e.t.c.
Mutiple message sorting
Sort mitple messages into geussed destinations
And to use qmail-local to deliver messages as instructed in the .qmail file.

The exact specifics and how to set getmail to use these features are in the manual, go read it if you want to know more. I suggest ether mbox or maildir personally.

Maildir is pretty simple there is a folder containing new, cur, and tmp directories full of e-mails. If you plan on checking e-mail often or automating it (as I do) this is probably for you. Each e-mail gets its own file in one of those directories which I personally think makes it better suited sharing messages but bad for FAT32 file systems (i.e. many small files).

We can make a mail directory like this on the command line, assuming we want ~/Mail. Or just make four directories in a GUI file manager.

mkdir -p ~/Mail/{new,cur,tmp}

You'll need to set the path to the mail directory as well to use Maildir. You can also set the user and file permissions to use. You've got to use the unix octal format, i.e. 0755 instead of u=rwx g=rx o=rw or some thing.

[destination]
type = Maildir 
path = ~/Mail/
user = rstf
filemode = 0600
Setting filemode to 0600 means only I and the root user have read-write permission to my mail.

Now if we want to use mboxrd we have to specify the type and path to the mbox file as well. The user option works here too. Also you need to consider the locktype option. It takes a string argument and you have a choice of 'lockf' which uses fcntl locking or 'flock' default as of this writing (getmail v4.7.0) is lockf.

[destination]
type = Mboxrd
path = ~/Mail/inbox
user = rstf
locktype = lockf

We can also set up filter sections to use stuff like clamav & spam assasion on our e-mail. Considering that the odds of a virus or trojan that can invect a windows machine through being ssh'd into a freebsd box that is using mutt to view mail fetched with getmail from a server that filters spam (optional /w my ISP) and scans for viruses (nice ISP). I don't blood ythink I need to filiter things through an Anti-Virus ! But if you like go read the documentation on how to set that up.

I think I'll be looking into spam assasion for my ISP account though so maybe I'll have some thing topost there.

The options section I don't think is required but I'd suggest you set your read_all and ether delete or delete_after options.

My suggestions

[options]
# fetch all mail on the server
read_all = true
# then delete it after its in our Maidir or Mboxrd destination(s)
delete = true

[options]
# fetch mail getmail has not seen before
read_all = false
# then delete old messages after 1 day
delete_after = 1

The bottom option deletes the messages you download today from your mail server (not your destination) the next time getmail checks for mail and sees that the old messages are '1' day old. Any integer number will do but not a floating point number. i.e. 4675 will work but 2.43 will not.

I have two getmail rc files one for each account
$ ls -R ~/.getmail                                             20:21
getmailrc-bell
getmailrc-sas
oldmail-mail.host.tld-110-username
oldmail-mail.host.tld-995-username
So I can run getmail and tell it which file to use so Ican deside which mailbox to check. I've made a pair of shell aliases in my shells rc file to save typing.

alias gm-bell='getmail -rgetmailrc-bell'
alias gm-sas='getmail -rgetmailrc-sas'

Ok, lets run getmail (I'll skip the alias), it will take a few seconds bu t if it takes a really long time you might want to make sure your system is configured correctly to resolve the hostnames.

rstf@Vectra$ getmail -rgetmailrc-sas                                                       20:22
getmail version 4.7.0
Copyright (C) 1998-2006 Charles Cazabon.  Licensed under the GNU GPL version 2.
SimplePOP3SSLRetriever:My_EmailAddr@sasclan.org@OurMailServer:
  0 messages retrieved, 0 skipped

Looks like I have no new mail in the account.

Ok, lets try some automation we can set cron jobs to run getmail -rRCFILE when ever we want on one or all of our files.

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