> ^1239_ would match any route coming from AS1239 *including* routes > originated in AS1239. This is because the underscore can match any > character including whitespace and the $ end-of-path anchor. >
Probably work in show command but not in the IOS policy. At the very least the '^1239_' is very sloppy and not POSIX compliant, while '^1239 .*' is. > ^1239 .* would match any route coming through AS1239 but *not* routes > originated in AS1239. This is presumably because I now have included a > specific space between the ^1239 and the .*. This will exclude ^1239$. > Actually '^1239 .*' would only match routes originated in AS1239. ^1239$ would only match the single AS_PATH AS1239 exclusively and so would '^1239 .*'. ^1239$ means... Matched string MUST start with a 1, then be proceeded by a 2, then proceeded by a 3, then proceeded with a 9 and end with a 9 to be true. '^1239 .*' means... Matched string MUST start with a 1, then be proceeded by a 2, then proceeded by a 3, then proceeded with a 9, then proceeded by 0 or more characters of any kind so AS1239 could be the only AS_PATH there. I am not sure how IOS processes the space as a litereal space or just a seperator between AS's. I had always thought IOS processed the AS_PATH as a string of characters so the space may be counted but I think the '_' is what forces the space to be counted as a space. > ^1239_.+ behaves the same way as ^1239 .*. This is because the + sign > expects one or more repetitions of at least one character following ^1239_. > No it does not. Remember * is 0 or more. + is 1 or more. Adding the + means you must have at least one character of any kind while the * could be empty. Makes a HUGE difference depending on the string you are matchinig against. -Julian Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=24914&t=24460 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
