Cyrus POP3 long line problem

[Vincent Fox]

On 6/14/2014 6:16 AM, Joseph Brennan wrote:
>
> Vincent Fox <vbfox at ucdavis.edu> wrote:
>
>> I have recently noticed that certain malformed messages hang POP3 clients.
>> The pattern is that the mesages all have obscenely long last lines. I
>> can see it
>> when I set up debug log dir for the account, that the download of the
>> message
>> proceeds fine up until 2048th character and then stops.
>
> How is that possible? The SMTP maximum is 1000 including the CR LF pair.
> I'm surprised a message like that is accepted by your MTA and/or LMTP. If
> Cyrus IMAP handles up to 2047 characters that's very generous.
>
>
As I researched further after this message I realized that it shouldn't.

When I look through my sendmail configuration at the various mailers
I note the SMTP have L=990, except relay which is L=2040.
BUT the LMTP mailer seems to have no L= at all!

So malformed message arrives directly at my MX server from spammer
and then is happily delivered by LMTP which doesn't seem to care about
long lines or do anything about it.   I suppose this wouldn't occur if I 
were
using SMTP to my backends but I thought it was preferred.

Yes I am realizing now this is not a Cyrus/POP problem per se, and I need
some layer on my mail router to take action on the message body issue.

Thanks!