1. Atom An atom is a single character, such as the following
| . |
Matches any single character |
| ^ |
Matches the beginning of the input string |
| $ |
Matches the end of the input string |
| \ |
Matches the character |
| – |
Matches a comma (,), left brace ({), right brace (}), the beginning of the input string, the end of the input string, or a space. |
2. Piece A piece is an atom followed by one of the following symbols
| * |
Matches 0 or more sequences of the atom |
| + |
Matches 1 or more sequences of the atom |
| ? |
Matches the atom or the null string |
3. Branch A branch is a 0 or more concatenated pieces
| a* |
Any occurrence of the letter "a", including none |
| a+ |
At least one occurrence of the letter "a" should be present) |
| ab?a |
This matches "aa" or "aba" |
| _100_ |
Via AS100 |
| ^100$ |
Origin AS100 |
| ^100 .* |
Coming from AS100 |
| ^$ |
Originated from this AS |
Examples
3-1-1, Filtering bgp output with route only origin from AS7018
Cisco Router#sh ip bgp regexp ^7018$
BGP table version is 199154652, local router ID is x.x.x.x
Status codes: s suppressed, d damped, h history, * valid, > best, i – internal,
r RIB-failure, S Stale
Origin codes: i – IGP, e – EGP, ? – incomplete
Network Next Hop Metric LocPrf Weight Path
*>i3.51.92.0/23 12.122.126.39 10 100 0 7018 ?
* i 12.122.126.39 10 100 0 7018 ?
*>i12.0.0.0/9 12.122.126.39 10 100 0 7018 i
* i 12.122.126.39 10 100 0 7018 i
*>i12.0.0.0 12.122.126.39 10 100 0 7018 i
:
:
3-1-2, Filtering bgp output with route origin from AS46164
Cisco Router#sh ip bgp regexp _46164$
BGP table version is 199155849, local router ID is x.x.x.x
Status codes: s suppressed, d damped, h history, * valid, > best, i – internal,
r RIB-failure, S Stale
Origin codes: i – IGP, e – EGP, ? – incomplete
Network Next Hop Metric LocPrf Weight Path
* i4.23.88.0/24 12.122.126.39 10 100 0 7018 46164 i
*>i 12.122.126.39 10 100 0 7018 46164 i
*>i4.23.88.0/23 12.122.126.39 10 100 0 7018 46164 i
:
:
3-2, Filtering bgp output with route pass thru AS6762
Cisco Router#sh ip bgp regexp _6762_
BGP table version is 199165809, local router ID is x.x.x.x
Status codes: s suppressed, d damped, h history, * valid, > best, i – internal,
r RIB-failure, S Stale
Origin codes: i – IGP, e – EGP, ? – incomplete
Network Next Hop Metric LocPrf Weight Path
*>i2.0.0.0/16 144.228.243.250 10 100 0 1239 6762 12654 i
* i 144.228.243.250 10 100 0 1239 6762 12654 i
*>i2.1.0.0/21 144.228.243.250 10 100 0 1239 6762 12654 i
* i 144.228.243.250 10 100 0 1239 6762 12654 i
:
:
3-4, Filtering bgp output with route only origin from AS1239 and directly attached with AS1239
Cisco Router#sh ip bgp regexp ^1239_[0-9]*$
BGP table version is 199175215, local router ID is x.x.x.x
Status codes: s suppressed, d damped, h history, * valid, > best, i – internal,
r RIB-failure, S Stale
Origin codes: i – IGP, e – EGP, ? – incomplete
Network Next Hop Metric LocPrf Weight Path
*>i8.3.213.0/24 144.228.243.250 10 100 0 1239 4739 i
* i 144.228.243.250 10 100 0 1239 4739 i
*>i8.10.245.0/24 144.228.243.250 10 100 0 1239 17151 i
* i 144.228.243.250 10 100 0 1239 17151 i
3-5, Filtering bgp output with route from difectly connected any AS in even future.
Cisco Router#sh ip bgp regexp ^([0-9]+)(_\1)*$
BGP table version is 199175920, local router ID is x.x.x.x
Status codes: s suppressed, d damped, h history, * valid, > best, i – internal,
r RIB-failure, S Stale
Origin codes: i – IGP, e – EGP, ? – incomplete
Network Next Hop Metric LocPrf Weight Path
*>i12.70.138.0/24 144.228.243.250 10 100 0 1239 i
* i 144.228.243.250 10 100 0 1239 i
*>i12.195.4.0/24 144.228.243.250 10 100 0 1239 i
3-6, Filtering bgp output with route learning from AS1239
Cisco Router#sh ip bgp regexp ^1239_
BGP table version is 199177194, local router ID is x.x.x.x
Status codes: s suppressed, d damped, h history, * valid, > best, i – internal,
r RIB-failure, S Stale
Origin codes: i – IGP, e – EGP, ? – incomplete
Network Next Hop Metric LocPrf Weight Path
*>i2.0.0.0/16 144.228.243.250 10 100 0 1239 6762 12654 i
* i 144.228.243.250 10 100 0 1239 6762 12654 i
*>i2.1.0.0/21 144.228.243.250 10 100 0 1239 6762 12654 i
3-7, Filtering bgp output with route only direct connected ASs
Cisco Router#sh ip bgp regexp ^[0-9]+$
BGP table version is 199177786, local router ID is x.x.x.x
Status codes: s suppressed, d damped, h history, * valid, > best, i – internal,
r RIB-failure, S Stale
Origin codes: i – IGP, e – EGP, ? – incomplete
Network Next Hop Metric LocPrf Weight Path
*>i3.51.92.0/23 12.122.126.39 10 100 0 7018 ?
* i 12.122.126.39 10 100 0 7018 ?
*>i4.0.0.0/9 4.68.185.60 10 100 0 3356 i
3-8, Filtering bgp output with route only direct connected ASN with letter 1, 7 and 4
Cisco Router#sh ip bgp regexp ^[174]+$
BGP table version is 199179097, local router ID is x.x.x.x
Status codes: s suppressed, d damped, h history, * valid, > best, i – internal,
r RIB-failure, S Stale
Origin codes: i – IGP, e – EGP, ? – incomplete
Network Next Hop Metric LocPrf Weight Path
*>i24.238.0.0/24 154.54.13.137 10 100 0 174 i
* i 154.54.13.137 10 100 0 174 i
*>i24.238.2.0/24 154.54.13.137 10 100 0 714 i
* i 154.54.13.137 10 100 0 714 i
3-9, Filtering bgp output with route origin from AS46164 and thru AS7018
Cisco Router#sh ip bgp reg ^7018_46164$
BGP table version is 199190289, local router ID is x.x.x.x
Status codes: s suppressed, d damped, h history, * valid, > best, i – internal,
r RIB-failure, S Stale
Origin codes: i – IGP, e – EGP, ? – incomplete
Network Next Hop Metric LocPrf Weight Path
* i4.23.88.0/24 12.122.126.39 10 100 0 7018 46164 i
*>i 12.122.126.39 10 100 0 7018 46164 i
*>i4.23.88.0/23 12.122.126.39 10 100 0 7018 46164 i
* i 12.122.126.39 10 100 0 7018 46164 i
3-10, Filtering bgp output with route locally origin
Cisco Router#sh ip bgp reg ^$
BGP table version is 199192287, local router ID is x.x.x.x
Status codes: s suppressed, d damped, h history, * valid, > best, i – internal,
r RIB-failure, S Stale
Origin codes: i – IGP, e – EGP, ? – incomplete
Network Next Hop Metric LocPrf Weight Path
*>i4.68.62.96/30 140.222.130.48 100 0 i
* i 140.222.130.48 100 0 i
*>i4.68.63.140/30 140.222.130.48 100 0 i
* i 140.222.130.48 100 0 i
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