If someone does not recite durood in dua and plainly asks Allah for what he wants, is his dua valid? Does he have to recite durood in dua or is it optional?
Please answer with proof.
The du'a' is valid however it's better to praise Allah and send salat, salam, and barak on Rasolullah(Sallallahu Alaihi Wa Sallam).
There's a lesson from in a hadith about prayer, goes as follows :
Fodalah ibn Ubayd narrated...Rasolullah(Sallallahu Alaihi Wa Sallam) heard a man making du'a' during prayer. He did not glorify Allah, nor did he send salah on Nabi.
Rasolullah(Sallallahu Alaihi Wa Sallam) said: "He hurried."
He then called him and said to him and who was not around:
If any of you prays, he should mention glorification of his Lord in the beginning and praise Him; he should then invoke blessings on the Prophet; thereafter he should supplicate Allah for anything he wishes.
Wording is from Sunan Abu Dawud
This is reported in two different chains of narrators.
Isnad from Sunan Abu Dawud =
حَدَّثَنَا أَحْمَدُ بْنُ حَنْبَلٍ، حَدَّثَنَا عَبْدُ اللَّهِ بْنُ يَزِيدَ، حَدَّثَنَا حَيْوَةُ، أَخْبَرَنِي أَبُو هَانِئٍ، حُمَيْدُ بْنُ هَانِئٍ أَنَّ أَبَا عَلِيٍّ، عَمْرَو بْنَ مَالِكٍ حَدَّثَهُ أَنَّهُ، سَمِعَ فَضَالَةَ بْنَ عُبَيْدٍ، صَاحِبَ
Isnad from Jami' at-Tirmidhi =
حَدَّثَنَا مَحْمُودُ بْنُ غَيْلاَنَ، حَدَّثَنَا عَبْدُ اللَّهِ بْنُ يَزِيدَ الْمُقْرِئُ، حَدَّثَنَا حَيْوَةُ بْنُ شُرَيْحٍ، حَدَّثَنِي أَبُو هَانِئٍ الْخَوْلاَنِيُّ، أَنَّ عَمْرَو بْنَ مَالِكٍ الْجَنْبِيَّ، أَخْبَرَهُ أَنَّهُ، سَمِعَ فَضَالَةَ بْنَ عُبَيْدٍ
Both come through a narrator named أَبُو هَانِئٍ الْخَوْلاَنِيُّ
He was truthful narrator but also made some mistakes when he reported hadiths.
However, the hadith gives a good advice and should be practiced. Sending salawat on Rasolullah(Sallallahu Alaihi Wa Sallam) is a very great thing.