diff --git a/jvb/Dockerfile b/jvb/Dockerfile
index 7062b5a..870bf53 100644
--- a/jvb/Dockerfile
+++ b/jvb/Dockerfile
@@ -3,7 +3,7 @@ ARG BASE_TAG=latest
 FROM ${JITSI_REPO}/base-java:${BASE_TAG}
 
 RUN apt-dpkg-wrap apt-get update && \
-    apt-dpkg-wrap apt-get install -y jitsi-videobridge2 jq curl iproute2 && \
+    apt-dpkg-wrap apt-get install -y jitsi-videobridge2 jq curl iproute2 dnsutils && \
     apt-cleanup
 
 COPY rootfs/ /
diff --git a/jvb/rootfs/defaults/jvb.conf b/jvb/rootfs/defaults/jvb.conf
index 900565d..689eada 100644
--- a/jvb/rootfs/defaults/jvb.conf
+++ b/jvb/rootfs/defaults/jvb.conf
@@ -1,12 +1,12 @@
+{{ $COLIBRI_REST_ENABLED := .Env.COLIBRI_REST_ENABLED | default "false" | toBool }}
 {{ $ENABLE_COLIBRI_WEBSOCKET := .Env.ENABLE_COLIBRI_WEBSOCKET | default "1" | toBool }}
 {{ $ENABLE_OCTO := .Env.ENABLE_OCTO | default "0" | toBool }}
 {{ $JVB_TCP_PORT := .Env.JVB_TCP_PORT | default "4443" }}
 {{ $JVB_TCP_MAPPED_PORT := .Env.JVB_TCP_MAPPED_PORT | default $JVB_TCP_PORT }}
 {{ $PUBLIC_URL_DOMAIN := .Env.PUBLIC_URL | default "https://localhost:8443" | trimPrefix "https://" | trimSuffix "/" -}}
-{{ $WS_DOMAIN := .Env.JVB_WS_DOMAIN | default $PUBLIC_URL_DOMAIN -}}
-{{ $WS_SERVER_ID := .Env.JVB_WS_SERVER_ID | default .Env.LOCAL_ADDRESS -}}
-{{ $COLIBRI_REST_ENABLED := .Env.COLIBRI_REST_ENABLED | default "false" | toBool }}
 {{ $SHUTDOWN_REST_ENABLED := .Env.SHUTDOWN_REST_ENABLED | default "false" | toBool }}
+{{ $WS_DOMAIN := .Env.JVB_WS_DOMAIN | default $PUBLIC_URL_DOMAIN -}}
+{{ $WS_SERVER_ID := .Env.JVB_WS_SERVER_ID | default .Env.JVB_WS_SERVER_ID_FALLBACK -}}
 
 videobridge {
     ice {
@@ -84,7 +84,6 @@ ice4j {
                 enabled = false
 {{ end -}}
             }
-
             static-mappings = [
 {{ if .Env.DOCKER_HOST_ADDRESS -}}
                 {
diff --git a/jvb/rootfs/etc/cont-init.d/10-config b/jvb/rootfs/etc/cont-init.d/10-config
index 769b153..b7ae088 100644
--- a/jvb/rootfs/etc/cont-init.d/10-config
+++ b/jvb/rootfs/etc/cont-init.d/10-config
@@ -1,8 +1,5 @@
 #!/usr/bin/with-contenv bash
 
-export LOCAL_ADDRESS=$(ip addr show dev "$(ip route|awk '/^default/ { print $5 }')" | grep -oP '(?<=inet\s)\d+(\.\d+){3}')
-export SENTRY_RELEASE="${SENTRY_RELEASE:-$(apt-cache policy jitsi-videobridge2 | sed -n '/Installed/p' | sed -e 's/[^:]*: //')}"
-
 if [[ -z $JVB_AUTH_PASSWORD ]]; then
     echo 'FATAL ERROR: JVB auth password must be set'
     exit 1
@@ -14,6 +11,16 @@ if [[ "$JVB_AUTH_PASSWORD" == "$OLD_JVB_AUTH_PASSWORD" ]]; then
     exit 1
 fi
 
+# On environments like Swarm the IP address used by the default gateway need not be
+# the one used for inter-container traffic. Use that one for our fallback ID.
+XMPP_SERVER_IP=$(dig +short ${XMPP_SERVER})
+export JVB_WS_SERVER_ID_FALLBACK=$(ip route get ${XMPP_SERVER_IP} | grep -oP '(?<=src ).*' | awk '{ print $1 '})
+
+# Local IP for the ice4j mapping harvester.
+export LOCAL_ADDRESS=$(ip route get 1 | grep -oP '(?<=src ).*' | awk '{ print $1 '})
+
+export SENTRY_RELEASE="${SENTRY_RELEASE:-$(apt-cache policy jitsi-videobridge2 | sed -n '/Installed/p' | sed -e 's/[^:]*: //')}"
+
 if [[ -f /config/custom-sip-communicator.properties ]]; then
     cat /config/custom-sip-communicator.properties > /config/sip-communicator.properties
 fi