Regexp for spam filter

Question

I've trying to set up some filters from spam mail on our Microsoft Exchange server.

I need to check the letter ad spam if there is in header "Recieved" more then 3 dots and it doesn't containt word "outlook"

Checking dots can be done by regex .*\..*\..*\..*

Checking if string doesn't contain word "outlook" can be done by regex ((?!outlook).)*$

I try to unite then in one expression ^(?=.*\..*\..*\..*)(?=((?!outlook).)*$) but doesn't work:(

What am I doing wrong?

Did my answer work for you? – Wiktor Stribiżew Jun 15 '18 at 07:13 — Wiktor Stribiżew, Jun 15 '18 at 07:13

Wiktor Stribiżew · Answer 1 · 2018-06-14T07:49:18.683

You may use

^(?!.*outlook)[^.]*(?:\.[^.]*){0,2}$

Details

^ - start of string
(?!.*outlook) - no outlook substring allowed anywhere on the line
[^.]* - any 0+ chars other than a .
(?:\.[^.]*){0,2} - 0, 1 or 2 occurrences of
- \. - a dot
- [^.]* - any 0+ chars other than a .
$ - end of string.

So, any string will be matched that has no outlook and that has 0, 1 or 2 dots only.

Note that in case you have multiple lines there, you will have to make . match multiple lines.

1 Answers1