# Crowdsecurity/rdns not adding reverse\_dns to alerts

**URL:** <https://discourse.crowdsec.net/t/crowdsecurity-rdns-not-adding-reverse-dns-to-alerts/2079>\
**Category:** crowdsec\
**Created:** [October 15, 2024, 7:59am UTC](https://discourse.crowdsec.net/t/crowdsecurity-rdns-not-adding-reverse-dns-to-alerts/2079 "2024-10-15T07:59:09Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![g00g1](https://avatars.discourse-cdn.com/v4/letter/g/6a8cbe/32.png) [@g00g1](https://discourse.crowdsec.net/u/g00g1)\
**Post date:** [October 15, 2024, 7:59am UTC](https://discourse.crowdsec.net/t/crowdsecurity-rdns-not-adding-reverse-dns-to-alerts/2079/1 "2024-10-15T07:59:09Z")

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I have installed crowdsecurity/rdns, ensured that it is enabled and restarted crowdsec. However, after following [guide](https://docs.crowdsec.net/docs/whitelist/create_postoverflow), I still can’t whitelist hosts with a specific reverse DNS.

Also I would like to ask if it is possible to verify rDNS in postoverflow to confirm FCrDNS.

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**Author:** ![thibault](https://dub1.discourse-cdn.com/flex013/user_avatar/discourse.crowdsec.net/thibault/32/2_2.png) [@thibault](https://discourse.crowdsec.net/u/thibault)\
**Post date:** [October 22, 2024, 7:25am UTC](https://discourse.crowdsec.net/t/crowdsecurity-rdns-not-adding-reverse-dns-to-alerts/2079/2 "2024-10-22T07:25:28Z")

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Hello,

Please provide more details about what you’re trying and what doesn’t work 🙂  
Maybe try turning your whitelists or the rdns postoverflow in debug mode.