Updated documentation for Linux

README.md

@@ -382,7 +382,9 @@ Otherwise, this project now automatically sets up Xdebug support with VS Code. I
 
 Running Docker on Linux should be pretty straight-forward. Note that you need to run some [post install commands](https://docs.docker.com/install/linux/linux-postinstall/) as well as [installing Docker Compose](https://docs.docker.com/compose/install/). These steps are taken care of automatically with Docker Desktop, but not on Linux.
 
-You may have to increase a virtual memory map count on the host system. It is required by [Elasticsearch](https://www.elastic.co/guide/en/elasticsearch/reference/current/vm-max-map-count.html).
+Be sure to see the "Linux only" documentation in the [docker-compose.dev.yml](https://github.com/markshust/docker-magento/blob/master/compose/docker-compose.dev.yml#L30) file. The `extra_hosts` param is required to be defined on Linux for proper DNS resolution.
+
+You may also have to increase a virtual memory map count on the host system. It is required by [Elasticsearch](https://www.elastic.co/guide/en/elasticsearch/reference/current/vm-max-map-count.html).
 
 Add following line to `/etc/sysctl.conf`:
 
@@ -390,6 +392,12 @@ Add following line to `/etc/sysctl.conf`:
 vm.max_map_count=262144
 ```
 
+To enable Xdebug on linux, you'll also need to open port 9001 on the firewall with:
+
+```
+sudo iptables -A INPUT -p tcp --dport 9001 -j ACCEPT
+```
+
 ### Blackfire.io
 
 These docker images have built-in support for Blackfire.io. To use it, first register your server ID and token with the Blackfire agent: