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Related Links for Custom Sites/Applications

• Best Practice
• SmartConsole Help
• Close URL strings with "/" at the end
• Solution if Application & URL Filtering Policy doesn't match
• Unable to bypass custom sites/applications in HTTPS inspection policy
• Measure CPU time consumed by Pattern Matcher

Recommendations

• Don't use * as it puts high load to the Pattern Matcher on the Security Gateway (it doesn't matter if it's with or without Regex)
• Don't put http: or https: in the string of the custom site
• Always put a / at the end of non-Regex domains
• If a special subdomain can be referenced, such as  www.sample.com/ avoid Regex and directly reference it
• Verify the common name of the custom site and test with this one as well, if it's different

Special considerations

• Regex syntax implicitly starts and ends with .*
• Non-Regex syntax implicitly ends with *
• Custom applications are matched only with the payload of a connection

Risk mitigation

• Many syntaxes allow more than intended, thoughtfully plan and test your syntax
• Workarounds might cause performance impacts, though they are always a good read
• Learn Regex! Verify your Regex syntax with online Regex generators. Understand your Regex!

Common mistakes

• checkpoint.com matches for checkpoint.com.crime.org
• *checkpoint.com/ matches for crime.org/checkpoint.com/
• *.checkpoint.com/ matches for crime.org/www.checkpoint.com/ 
• Regex \/checkpoint.com\.com matches for crime.org/checkpoint.com/
• Regex \.checkpoint\.com matches for www.checkpoint.com.crime.org