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The latter method is much faster and less resource-intensive than the string matching approach.
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As an example, very basic AS Path filter that matchers ASN 1234 anywhere in the middle of the AS-path:
| Code Block | ||
|---|---|---|
| ||
/routing/filter/rule/add
chain=myChain rule="if (bgp-as-path .1234.) {accept}" |
Supported Operators
| Operator | Description | Example | Example Explained | Example Matches | ||
|---|---|---|---|---|---|---|
| ^ | Represents the beginning of the path | ^1234 | will math AS-path starting with ASN 1234 | |||
| $ | Represents the end of the path | 1234$ | will match AS-path of origin ASN 1234 | |||
| * | Zero or more occurrences of the listed ASN | ^1234*$ | will math Null as-path or as-path where ASN 1234 may or may not appear multiple times | Math: 1234 1234 1234 1234 Null path No Match: 1234 5678 | ||
| + | One or more occurrences of the listed ASN | 1234+ | will match AS-path where ASN 1234 appears at least once | Match: 1234 3 1234 6 No match: 12345 678 | - | Represents the range |
| ? | Zero or one occurrence of the listed ASN | ^1234? 5678 | will match AS-path that may or may not start with ASN 1234 appearing once. | Match: 5678 1234 5678 No match: 1234 1234 5678 12345 5678 | ||
| . | One occurrence of any ASN | ^.$ | will match any AS-path with length of one. | Match: 12345 45678 No match: 1234 5678 | ||
| | | Match one of two ASNs on each side | ^(1234|5678) | will match AS-path starting with ASN 1234 or 5678 | Match: 1234 5678 1234 5678 No Match: 91011 | ||
[ ] | Represents the set of AS numbers where one AS number from the list must match. It is also possible to reference the pre-defined num-sets from num-sets with [[numset_name]] | ^[1234 5678 1-100] | will match AS-path that starts with 1234 or 5678 or from the range of 1 to 100 | Match: 1234 99 5678 No Match: 101 | ||
() | Group of regexp terms to match | ^(1234$|5678) | will match AS-path that starts and ends with 1234 or AS-path that starts with 5678 | Match: 1234 5678 9999 No Match: 1234 5678 |
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