Techy: Removing an rate limit block from Exim

During testing/investigation of an issue, I had to send “bad emails” to my Exim based mail server which after a number of attempts blocked me using the rate limit that had been configured:

451-The server has reached its limit for processing requests from your host.
451 Please try again later.

I didn’t want to wait for over an hour for the block to clear so I had to find out how to clear the block manually. On the mail server, I found the Exim data files in /var/spool/exim/db and using the exim_dumpdb tool to view the “ratelimit” block list:

# exim_dumpdb /var/spool/exim/ ratelimit

and then limiting it to the sending IP address (which I had checked via /var/log/exim_rejectlog ):

# exim_dumpdb /var/spool/exim/ ratelimit | grep 2001:db8:9:a::
28-Oct-2022 16:50:01.247104 rate:      1.877 key: 1h/per_mail/2001:db8:9:a::
28-Oct-2022 16:50:14.986765 rate:      1.937 key: 1h/per_conn//2001:db8:9:a::

Okay, that’s confirmed the block – but now to remove it. To do this, I had to use the “practically no documentation and no ui” tool exim_fixdb :

exim_fixdb /var/spool/exim/ ratelimit

It then just showed a prompt “>” with no instructions. But if the “key” was provided:

# exim_fixdb /var/spool/exim/ ratelimit
Modifying Exim hints database /var/spool/exim//db/ratelimit
> 1h/per_mail/2001:db8:9:a::
28-Oct-2022 16:50:01
0 time stamp: 28-Oct-2022 16:50:01
1 fract. time: .247104
2 sender rate: 1.877

Pressing “d” then deleted that record (and I repeated it for the other entry). Once I had finished, I just used “q” to quit exim_fixdb.

Hope it helps!