BGP AS Path Filter Example

Hi Rene,

Great topic! However, I am having trouble understanding the following expressions: ^3257_[0-9]$
Ok, so far I understand that the ^3257 is the start of the AS path, so this would be a directly connected AS. I also understand that _ represents any AS paths after 3257 and you would have to define the $ expression to define the last AS path to match on, otherwise all AS paths after 3257 would be considered.
However, i don’t get the [0-9]
at all…Can you clarify this by also using the + and ? in substitution for the *?
I read your BGP Regular Expression topic but its still not clear…

Thanks!
Mario