# SMTP-config voor localhost of 172.17.0.1 werkt niet, hoe te debuggen **URL:** https://meta.discourse.org/t/smtp-config-to-use-localhost-or-172-17-0-1-is-not-working-how-to-debug/229056 **Category:** Support **Created:** [5 juni 2022 om 10:17 UTC](https://meta.discourse.org/t/smtp-config-to-use-localhost-or-172-17-0-1-is-not-working-how-to-debug/229056 "2022-06-05T10:17:45Z") **Posts on this page:** 1 **Showing post:** 2
### Author: ![meglio](https://sea3.discourse-cdn.com/meta/user_avatar/meta.discourse.org/meglio/32/71444_2.png) [@meglio](https://meta.discourse.org/u/meglio) #### Post date: [9 juni 2022 om 10:49 UTC](https://meta.discourse.org/t/smtp-config-to-use-localhost-or-172-17-0-1-is-not-working-how-to-debug/229056/2 "2022-06-09T10:49:40Z")
Turns out the traffic needs to be redirected, read more here: > [@Use Protonmail Bridge with Discourse](https://meta.discourse.org/t/use-protonmail-bridge-with-discourse/229503): > > Problem: a) Protonmail Bridge cannot listen to IP other than 127.0.0.1, and b) Discourse in a Docker container cannot send SMTP requests to 127.0.0.1 of the host machine. Solution: We configure it to send to 172.17.0.1 (the Docker’s bridge IP on the host machine), and then redirect to 127.0.0.1, on which the Protonmail Bridge is listening. We do it with using Socat. How To Start by installing Socat: apt install socat We will run Socat as a service. Create service file: nano /etc/systemd/sy… --- _[View the full topic](https://meta.discourse.org/t/smtp-config-to-use-localhost-or-172-17-0-1-is-not-working-how-to-debug/229056)._