When logging into Firmcheck, with Multi-Factor Authentication (MFA) enabled, you now have the option to "Trust this location for 30 days".
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By selecting this box at work, then for 30 days, you will not be required to enter your token whilst at the office. Workplaces typically have a static IP address that does not change.

If you work from home, you can still trust this location, however, residential homes typically do not have a static IP address but a dynamic address. This means if your internet is reset, your IP address will change, so the location is no longer trusted.