MS Office365 'IMAP' server

[Richard Lewis]

At Thu, 19 Feb 2015 12:37:25 -0700,
Lucien Pullen wrote:
> 
> Also sprach Richard Lewis on 2015-02-19:
> > However, I really would like to find a solution to this problem. I've
> > tried asking my organisation's IT services department but they tend to
> > ignore my tickets, I guess because they have no idea. I found some
> > mention of throttling in the MS server
> > <http://www.linux-france.org/prj/imapsync_list/msg01785.html> which
> > could be relevant.
> >
> > Does anyone have any suggestions how I could go about investigating
> > this? Are there any settings in offlineimap that might give me more
> > information about what's going on?
> 
> I set up an IPFW rule to throttle local->remote at some point.  From the
> IMAPsync message, it looks like this may help.  Kludge in the meanwhile
> to patching, but maybe something like this will slow you down enough to
> not hit the ImapCutoffBalance:
> 
> --8<---------------cut here---------------start------------->8---
> add 100 pipe 1 from any to any dst-port 993 out
> 
> pipe 1 config bw 200KBits/s
> --8<---------------cut here---------------end--------------->8---

Thanks for this suggestion. I don't have IPFW on Debian, but I tried
this instead:

# create a new root queue
$ sudo tc qdisc add dev eth0 root handle 2 htb default 1

# create a new root class which defines the default rules, 1gbit
$ sudo tc class add dev eth0 parent 2: classid 2:6 htb rate 1gbit

# define a child class with the max speed we want
$ sudo tc class add dev eth0 parent 2:6 classid 2:100d htb rate 200kbit

# create a filter which matches traffic heading to port 993 and applies the 200kbit class
$ sudo tc filter add dev eth0 parent 2: protocol ip pref 4 u32 match ip dport 993 0xffff classid 2:100d

However, it doesn't seem to have fixed my problem. This is the first
time I've experimented with traffic shaping so there's a good chance I
could be doing something wrong, rather than traffic shaping not being
the answer here.

> As far as patching goes, could you open a connection to your server and
> request the capabilities list?  (Shell for OpenSSL, asterisk is IMAP
> prompt. Replace googlemail with your server.)
> 
> --8<---------------cut here---------------start------------->8---
> % openssl s_client -connect imap.googlemail.com:993 -crlf -quiet
> * OK Gimap ready for requests from ~~~~~ k85mb63340721ita
> a CAPABILITY
> * CAPABILITY IMAP4rev1 UNSELECT IDLE NAMESPACE QUOTA ID XLIST CHILDREN X-GM-EXT-1 XYZZY SASL-IR AUTH=XOAUTH AUTH=XOAUTH2 AUTH=PLAIN AUTH=PLAIN-CLIENTTOKEN
> a OK Thats all she wrote! k85mb63340721ita
> --8<---------------cut here---------------end--------------->8---

It says:

* CAPABILITY IMAP4 IMAP4rev1 AUTH=PLAIN UIDPLUS MOVE ID CHILDREN IDLE NAMESPACE LITERAL+

Thanks,
Richard