EricP's questions

I'm using courier imap. When a mail client creates a new folder, it's created on the filesystem with 640 permission. I need it to be writable by the group, or 660. I currently have /etc/courier/imapd IMAP_UMASK=007, but that's not enough.

I'm not sure what else to try. Any ideas? I'm using ubuntu server 12.04.

EDIT: I added a 50pt bounty to this. For an acceptable answer, I need a way to make it work from a package in a standard repo. If I download source and compile it myself, it won't be automatically kept up to date with security fixes.

If I don't find a better answer, I'll add code to the admin script to call another sudo approved script to chmod -R the whole directory before every change. But this is kind of hack-ish.

In /etc/courier/authmysqlrc, I have

MYSQL_QUOTA_FIELD CONCAT(quota, 'S')

But connecting to the account via RoundCube or Thunderbird with the Display Quota plugin shows an unlimited/unknown quota. In the quota field, I have entered 1000000, and this table/row is otherwise working perfectly for authentication.

I enabled mysql logging and checked the query log for the query that courier is executing for auth. When I execute it myself it works fine and correctly returns "1000000s" for the quota.

I'm using Ubuntu Server 12.04. Any ideas?

I've successfully setup courier+postfix to work with multiple email domains on the same server. At the moment I have these lines in /etc/courier/imap-ssl:

TLS_CERTFILE=/etc/courier/imapd.pem
TLS_TRUSTCERTS=/etc/ssl/certs

Changing them to this works great:

TLS_CERTFILE=/home/certs/certs/certificate.pem.ww2.endofstars.com
TLS_TRUSTCERTS=/home/certs/chains/endofstars.crt

The first contains the cert from the authority and my private key. The second has the certificate chain. Thunderbird doesn't show my customers the "No legetimate business will used unsigned certs" message, and running:

openssl s_client -connect ww2.endofstars.com:993

returns this, which makes me think it's working. But it's downhill from there. When I change my TLS_CERTFILE setting to:

TLS_CERTFILE=/home/certs/certs/certificate.pem

Thunderbird once again complains about an invalid cert. This file doesn't exist, but the imap-ssl docs say that it should automatically append the host name in order to find the certificate.pem.ww2.endofstars.com file. Using openssl to query it again shows this error, and mail.log reports:

imapd-ssl: couriertls: /home/certs/certs/certificate.pem: error:02001002:system library:fopen:No such file or directory

It's not appending the host name. The comments in imap-ssl say the multi-domain approach is "GnuTLS only", but I'm not sure how to tell if I have it installed. Running ldd /usr/sbin/couriertcpd shows:

linux-vdso.so.1 =>  (0x00007fffa75ff000)
libgdbm.so.3 => /usr/lib/x86_64-linux-gnu/libgdbm.so.3 (0x00007fcff8433000)
libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007fcff8076000)
/lib64/ld-linux-x86-64.so.2 (0x00007fcff8640000)

But I don't know if I'm doing it right, or it it would show whether gnutls is used. I'm on ubuntu server 12.04.

I'm trying to understand the built-in IO cache on Windows. If an application writes to a file, and then reads/writes it multiple subsequent times, it seems that the IO cache should allow this to happen as fast as system memory will allow? Then Windows will gradually write changes back to the physical disk in a non-blocking way?

However, I've seen other ramdisk-related questions on this site where users see significant gains by mounting a portion of system memory as a disk drive. If the IO cache works as I described above, why is this even necessary? Does Windows have settings to tweak this?

These lead up to my real question: Is there a point to using a ramdisk and manually syncing changes back to a physical disk, even minutes or hours later?

Edit: Fixed DMA vs IO Cache misconception corrected in Evan Anderson's reply.