diff --git a/README.md b/README.md
index 6daa301..4d43069 100644
--- a/README.md
+++ b/README.md
@@ -288,7 +288,7 @@ which is typically at `/etc/postfix/main.cf` on Debian based operating
 systems:
 
 ```
-# master.cf
+# main.cf
 
 # Support the default VERP delimiter.
 recipient_delimiter = +
diff --git a/core/README.md b/core/README.md
index a79403b..fd015c6 100644
--- a/core/README.md
+++ b/core/README.md
@@ -40,7 +40,8 @@ These are the variables that you MUST change before deploying:
 These are the variables that you don't need to change if you are using a
 standard version of docker-compose.yaml from this repository.
 
-- `MM_HOSTNAME`: Default value is `mailman-core`
+- `MM_HOSTNAME`: Which IP should Core bind to for REST API and LMTP. If not
+  defined output for `hostname -i` command is used.
 
 - `SMTP_HOST`: IP Address/hostname from which you will be sending
   emails. Default value is `172.19.199.1`, which is the address of the Host OS.
diff --git a/core/assets/run.sh b/core/assets/run.sh
index e4ff893..4fedd56 100755
--- a/core/assets/run.sh
+++ b/core/assets/run.sh
@@ -25,10 +25,11 @@ function wait_for_postgres () {
 # Empty the config file.
 echo "# This file is autogenerated at container startup." > /etc/mailman.cfg
 
-# Check if $MM_HOSTNAME is set, if not, set it to a default value.
-# TODO: Factor this out to a function.
+# Check if $MM_HOSTNAME is set, if not, set it to the value returned by
+# `hostname -i` command to set it to whatever IP address is assigned to the
+# container.
 if [[ ! -v MM_HOSTNAME ]]; then
-	export MM_HOSTNAME='172.19.199.2'
+	export MM_HOSTNAME=`hostname -i`
 fi
 
 if [[ ! -v SMTP_HOST ]]; then