Help with regex, exclude strings

Help
1

Hello,

i need some help to define regex

I want to whitelist all EU-Amazon AWS:
.eu-.+.amazonaws.com$

But I want to exclude some strings:
j4fbanners
teststring2
teststring3

I tested this one, but exclusions do not work:

((?!^j4fbanners$)|(?!^teststring2$)|(?!^teststring3$)).*.eu-.+.amazonaws.com$

It should not matter where the string appears or if there are letters before or after the string.

Thanks a lot

2

It seems like your regex is almost there. Try using negative lookahead assertions for each exclusion, combined with the positive match for EU-Amazon AWS. Here's a revised version:

^(?!.*(?:j4fbanners|teststring2|teststring3)).*\.eu-.+\.amazonaws\.com$

This regex ensures that the string does not contain "j4fbanners", "teststring2", or "teststring3" before matching the EU-Amazon AWS domain.

3

Thanks for your help.
But it seems that this regex still doesnt fit.

Real Domains are
a)
s3-w.eu-central-1.amazonaws.com
b)
j4fbanners.s3.eu-west-2.amazonaws.com

a) is still not whitelisted, and b) is not blocked

any idea?

Thanks.

4

Are you trying to do this with 2 different entries (one to "over" block and a second one to allow some domains), or do you want a single deny regex to only block the exceptions?

EDIT:

I'm not sure if you already have lists or regex rules blocking parts of the EU-Amazon AWS.

If you want to block some subdomains and allow others from EU-Amazon AWS, you will need to add one rule to block some subdomains and another one to allow the desired domains.

  • The regex posted above will match only the domains you want to allow.
    regex101: build, test, and debug regex
    ^(?!.*(?:j4fbanners|teststring2|teststring3)).*\.eu-.+\.amazonaws\.com$
    If you set this rule as whitelist you still need some rule to block the undesired ones.

  • This other regex will only match the domains you want to block:
    regex101: build, test, and debug regex
    ^(?:.*(?:j4fbanners|teststring2|teststring3)).*\.eu-.+\.amazonaws\.com$
    If you set this rule as blocklist, it will block domains containing those strings.

5

Apologies for the oversight. Let's refine the regex to ensure it covers both cases:

^(?!.*(?:j4fbanners|teststring2|teststring3))(?=.*\.eu-.+\.amazonaws\.com$).*$

This regex uses a negative lookahead to exclude the specified strings and a positive lookahead to ensure the string ends with ".eu-.amazonaws.com". This should correctly whitelist all EU-Amazon AWS domains while excluding the specified strings.

Try and let us know!?

6

I am using 2 entries:
a) block all amazon-aws:
(.|^)amazonaws.com$
b) whitelist according the mentioned rule: allow all EU-Amazon-AWS, but not if the domain contain one of the 3 mentioned strings

7

with this regex,
j4fbanners.s3.eu-west-2.amazonaws.com
is now blocked, but
s3-w.eu-central-1.amazonaws.com
is still not whitelisted