Manual:Regular Expressions

RouterOS support POSIX regular expression syntax (POSIX standard), with some exceptions:

• '{}' bounds are not supported;
• "()" must not be empty;
• equivalence classes are not supported ("[[.ch.]]");
• collating elements are not supported ("[[=a=]b]");
• matching is done in single pass, no backtracking.

Following services in RouterOS are using Regexps:

• firewall L7 matchers
• BGP filters
• CAPSMAN provisioning
• TFTP
• Web Proxy
• Hotspot Walled Garden
• DNS
• Console with '~' operator