I have already the following header map which works fine:
match protocol http header Host header-value abc.def.example.com*
Now I need to match whether the subdomain "def" is present or not. So, would the following accomplish this:
match protocol http header Host header-value abc.*example.com*
Actually the first one is incorrect.
But it will work.
What you need is this
match protocol http header Host header-value abc\.(def\.)?example\.com
Press -v to insert the '?'