I can't imagine most of the Farage fan club will care overly about his NATO or Ukraine positions, if anything they'd probably be in favour of Britain minding its own business. His target demographic is nativist, much like Trump's, so he's appealing to their basic instincts even as he alienates his chances of going wider. And I suspect he doesn't really care about wider, after all he's not actually thinking he can win the election unless hes completely delusional, and he's never struck me as that. He knows what his top whack of voters will be this time round and can quite happily appeal to that while also nodding into the far-right trends both in the EU and US, which have been very much Putin-sympathetic.
The reasons for that are potentially a more interesting question. Ideologically I can see it - Russia represents a great deal of what far-right types worldwide hanker after. Led by an intelligent, successful strongman, confident, aggressive, traditionalist and socially conservative to the point of serious repression.