Howdy,
Just upgraded to 7523 from 7503 two nights ago, and I have had some Apple devices starting to
get IDS blocks. (DoS - IMAP - 100 in 10 Min)
Here is a bit of the IMAP log: (Straight extract no intervening entries)
01:02:05.516 [24.108.146.168][18439537] connected at 2020-08-24 1:02:05 AM
01:02:06.391 [24.108.146.168][18439537] disconnected at 2020-08-24 1:02:06 AM
01:02:06.438 [24.108.146.168][62848178] connected at 2020-08-24 1:02:06 AM
01:02:06.438 [24.108.146.168][62848178] "421 Server is busy, try again later." response returned.
01:02:06.438 [24.108.146.168][62848178] IP is blacklisted
01:02:06.438 [24.108.146.168][62848178] disconnected at 2020-08-24 1:02:06 AM
01:02:06.516 [24.108.146.168][65168805] connected at 2020-08-24 1:02:06 AM
01:02:06.516 [24.108.146.168][65168805] "421 Server is busy, try again later." response returned.
01:02:06.516 [24.108.146.168][65168805] IP is blacklisted
01:02:06.516 [24.108.146.168][65168805] disconnected at 2020-08-24 1:02:06 AM
It goes from just working to starting to block on that IP. It has happened to two clients in different geographic locations. Definitely iDevices.
After the 60 min block, it starts working again, but will return at some random time.
And I have seen the other IMAP errors discussed as well, but I have not rolled back, maybe tonight.
Thanks,