ACL denied values

Hello guys,

We had recently a user agent which was added to the ACL denied list. When we removed the entry from the denied list, it immediately was added again to the list.

After a reboot of that user-agent he was not added anymore to the list.

For us it was not really clear why he was added again everytime to the list. We checked our realm-config and these are the related settings:

    access-control-trust-level       low

    invalid-signal-threshold        20

    maximum-signal-threshold        1000

    untrusted-signal-threshold       5

    nat-trust-threshold           0

    max-endpoints-per-nat          5

    nat-invalid-message-threshold      0

    wait-time-for-invalid-register     0

    deny-period               1800

Can someone explain me exactly what these values mean or refer to an article which explains this in an easy way?