Monitor daemon for exim4 logs

[Paulo Marcel Coelho Aragao <pmcaragao-ag@yahoo.com>]

Hi,

I have Debian sid running on a standalone laptop. exim4 is my MTA, Yahoo the 
smarthost, and fetchmail pulls mails from Yahoo and Gmail via POP3.

Today I had the unpleasant surprise that Yahoo changed the canonical name of 
its SMTP relay server, and mails I wrote during the day were bounced back by 
Yahoo. As I map my login name to my Yahoo account name via 
/etc/email-addresses, exim4 kept trying to relay them to Yahoo, bounce back, 
same story... Result: all mails were frozen in exim4. After changing Yahoo's 
canonical name in /etc/exim4/passwd.client, I forced delivery of the frozen 
messages and had hell to edit one by one, to remove exim4's headers, and 
resend them.

I realized that I should be monitoring exim4 logs for errors, so that I'd know 
when a message is frozen.

Would anybody have recommendations of lightweight monitors for exim4 logs, 
something appropriate to a standalone machine with a single user ?

Thanks for your attention
Paulo