What is the ruling concerning eating after the cannon has been fired?

 

The cannon of Ramadan
Firing the cannon in Ramadan is a traditional practice in some Muslim countries; it signifies the arrival of sunset in the evenings, and the approach of dawn in the morning. The cannon signaling the approach of dawn is usually fired 15 to 20 minutes before dawn as a precautionary measure.
Between sunset and the arrival of dawn, it is permissible for a person who intends to fast to eat, drink, and do anything that is permissible for a non-fasting person. When dawn breaks, a person must abstain from eating and drinking; he must spit out any food in his mouth, because the fasting hours start at the break of dawn.
Imam Bukhari reported in his Sahih that the Prophet [(peace and blessings be upon him) instructed his Companions, may God be pleased with them, to continue eating and drinking until ibn Um Maktum makes the call for Dawn Prayers (when the break of dawn has been confirmed).

 

The Ruling

It is permissible to eat and drink a few minutes after hearing the cannon but before the arrival of dawn; the fast will be valid.

And God Almighty knows best.