Verizon Community Strings
Verizon Internet Dedicated customers that run BGP can send community strings with their route advertisements to modify the Verizon Local Preference, increase the AS path length, control which routes are advertised to peers, contain routes within a continental AS, or black hole (drop) traffic at the Verizon network edge, to reduce the impact of a DDoS attack.
The following table lists the community tags that would be used for AS 701, associated BGP attribute and value (if applicable), and resulting action.
| Community Tag | Attribute | Value | Action |
| 701:80 | Local Pref | 80 | Least preferred |
| 701:90 | Local Pref | 90 | Less preferred |
| 701:100 | Local Pref | 100 | Default |
| 701:110 | Local Pref | 110 | More preferred |
| 701:120 | Local Pref | 120 | Most preferred |
| 701:1 | AS Path | 701 701 | Prepend the Verizon AS 701 one time |
| 701:2 | AS Path | 701 701 701 | Prepend the Verizon AS 701 two times |
| 701:3 | AS Path | 701 701 701 701 | Prepend the Verizon AS 701 three times |
| 701:20 | Keep route within Verizon Autonomous Systems (do not send to peers) | ||
| 701:30 | Refer to Note (keep route within regional Verizon AS and do not send to peers) | ||
| 701:9999 | Refer to Note (black hole the route at Verizon network edge devices) |
Table A-1
Note 1: Verizon has several AS numbers assigned to different regions of the world:
| 701 | North America |
| 702 | Europe/Middle East/Africa |
| 703 | Asia-Pacific |
| 14551 | Latin America/South America |
The AS portion of the community tag values should be changed appropriately for use in different Verizon regions.
Note 2: For technical reasons, customers who wish to use the black hole community must enable EBGP multihop (although BGP is still configured between the circuit addresses).
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