the agnivesya grihsutra suggests that only Kshatriyas,vaishayas, and shudras are allowed to wear a tripundra(1.18). Some Vaishnavas use it to say that a brahmin shouldn't be allowed to wear a tripundra. Can some scriptural inferences confirm whether tripundra can be worn by Brahmins?
Yes, a brahmana can have tripunda. In fact, he should have more tripundas than others.
O Brāhmaṇa, a Brāhmaṇa should always have twelve Puṇḍras. O son, Kṣatriyas should have four. It is prescribed (in Smṛtis) that Vaiśyas should have two Puṇḍras. It is laid down that women and Śūdras should have only one Puṇḍra.
The following are the parts of the body where a Brāhmaṇa should have his twelve sacred marks: forehead, belly, chest, hump of the neck, arms, ears, back, right side and lower part of the spine, and head, O sinless one.
A Kṣatriya should have the sacred marks on his forehead, chest and the arms; a Vaiśya on his forehead and chest and a Śūdra and women should wear the sacred mark on the forehead.
According to Shiva Purana people of all varnas can have Tripundra.
- People of all varṇas and Āśramas shall put on Tripuṇḍra on the forehead or dust their bodies with the mantras mentioned in the Jābāla-Upaniṣad or if no mantra is used they shall do the same with reverence.
Devi Bhagavatam say that it is necessary for a brahmin to have Tripundra.
Unless the Brāhmaṇas use the curved Tripuṇḍras, their meditation won’t be successful; they will not have liberation, knowledge, nor their asceticism would bear any fruit. As the Śūdras have no right in the study of the Vedas, so the Brāhmaṇs have not any right to perform the worship of Śiva, etc., unless they use the Tripuṇḍras.
Devi Bhagwatam 11:12 21-22
Here are the proofs that a Bramhin can wear Tripundra
The Bramhins and others , the householders and such persons should apply Bhasma in 3 stripes(Tripundra) according to direction set forth in the agamas. It is laid down in the scriptures that 3 stripes of Bhasma may be drawn in 5,8,16 or 32 parts of the body. (Kamika Agama Part 1 Page 63 Verses 70-71)
The God Siva is always hidden under the cover of ashes; so the Saivas, the devotees of Siva are to use the Tripundra. The Brahmanas are to use daily this Tripundra. Brahma is the Prime Brâhmin. When He used Tripundra on His forehead, what need to tell, then, that every Brâhman ought always to use it! Never fail, out of error, to besmear your body with the ashes as prescribed in the Vedas and worship the Siva Lingam. The Sannyasins are to apply Tripundra on their forehead, arms, chest, uttering the Triyamvaka mantra with Om prefixed and also the five lettered mantra of Siva “Om Namah Sivâya.” The Brahmâchâris should use Tripundra of ashes, obtained from their own fire, uttering the mantra “Triyayusam Jamadagneh,” etc., or the mantra “Medhâvî”, etc (Devi Bhagavatam 1)