Fiqh-us-Sunnah Volume 1, Purification and Prayer, Fiqh 1.046A.

For the resident, this period is one day and night. For the traveller, it is three days and nights. Said Safwan ibn ‘Assal, “We were ordered (by the Prophet) to wipe over the socks if we were in a state of purity when we put them on, for three days if we were travellers, and for one day and night if we were residents. We did not remove them unless we were in post-sex impurity.” (Related by ash-Shafi, Ahmad, Ibn Khuzaimah, at-Tirmizhi, and an-Nasa’i, who graded it sahih.)

Shuraih ibn Hani said, “I asked ‘Aishah about wiping over socks and she answered, ‘For the traveller, three days and three nights; for the resident, one day and night.” This hadith is related by Ahmad, Muslim, at-Tirmizhi, an-Nasa’i and Ibn Majah. Of its authenticity, al-Baihaqi says, “This is the most authentic report on this topic.” Some say that the duration begins with the time of the wiping, while others say it begins from the time of nullifying the ablution after wearing the socks.