The solutions posted here do not account for the fact that some of your hosts are the same..
When i need to enumerate items, I use this trick:
x <- c(
"95b4ae6d890e4c46986d91d7ac4bf08200000W",
"95b4ae6d890e4c46986d91d7ac4bf08200000W",
"95b4ae6d890e4c46986d91d7ac4bf08200000V",
"95b4ae6d890e4c46986d91d7ac4bf08200000V",
"95b4ae6d890e4c46986d91d7ac4bf08200000Z",
"95b4ae6d890e4c46986d91d7ac4bf08200000Z",
"95b4ae6d890e4c46986d91d7ac4bf082000011",
"95b4ae6d890e4c46986d91d7ac4bf082000011",
"95b4ae6d890e4c46986d91d7ac4bf082000011",
"95b4ae6d890e4c46986d91d7ac4bf082000011",
"95b4ae6d890e4c46986d91d7ac4bf08200000H",
"95b4ae6d890e4c46986d91d7ac4bf08200000H"
)
paste0("host", xtfrm(x))
which gives you
[1] "host3" "host3" "host2" "host2" "host4" "host4" "host5" "host5" "host5" "host5" "host1" "host1"
edit: originally hat the hacky as.integer(as.factor(x)) till i remembered xtfrm()