All forwarding across your account is counted against one gigabyte a month. The counter resets on the first.

What that is in practice

Ordinary mail is a few kilobytes. A gigabyte is tens of thousands of messages. Accounts that reach it almost always have one specific cause: a list that sends large attachments, a monitoring system pointed at an alias, or a shared address collecting scanned documents.

At the edge

Past the cap, incoming mail is refused with a permanent error. The sender gets a bounce and knows it did not arrive, which is the honest outcome. Accepting mail we intend to discard would leave everybody believing something arrived.

Bringing it down

• Switch off the address that generates the volume. The counters on each alias show which one it is.
• If it is one mailing list, unsubscribe rather than block: the traffic stops at the source.
• For a genuinely high volume address, use a domain you own and a mailbox at your own provider, and keep the aliases here for the addresses that need to be disposable.

If you are near it every month

Write to us and say what the traffic is. The number exists because forwarding costs bandwidth on a rented server that is paid for by donations, and it is a number, not a judgement: if the use is legitimate and the service can carry it, we would rather adjust than lose you.