IP Tagging

The HTTP IP Tagging filter sets the header x-envoy-ip-tags with the string tags for the trusted address from x-forwarded-for. If there are no tags for an address, the header is not set.

The implementation for IP Tagging provides a scalable way to compare an IP address to a large list of CIDR ranges efficiently. The underlying algorithm for storing tags and IP address subnets is a Level-Compressed trie described in the paper IP-address lookup using LC-tries by S. Nilsson and G. Karlsson.



The IP Tagging filter outputs statistics in the http.<stat_prefix>.ip_tagging. namespace. The stat prefix comes from the owning HTTP connection manager.

Name Type Description
<tag_name>.hit Counter Total number of requests that have the <tag_name> applied to it
no_hit Counter Total number of requests with no applicable IP tags
total Counter Total number of requests the IP Tagging Filter operated on


The IP Tagging filter supports the following runtime settings:

The % of requests for which the filter is enabled. Default is 100.