diff --git a/setup/argparser.sh b/setup/argparser.sh
index 4ecde6e14..9869492ec 100644
--- a/setup/argparser.sh
+++ b/setup/argparser.sh
@@ -7,8 +7,9 @@ json="${source_dir}/../node_modules/.bin/json"
 arg_api_server_origin=""
 arg_fqdn=""
 arg_admin_location=""
+arg_admin_fqdn=""
 arg_zone_name=""
-arg_is_custom_domain="false"
+arg_is_custom_domain="false" # can be removed after 1.9
 arg_retire_reason=""
 arg_retire_info=""
 arg_token=""
@@ -33,9 +34,11 @@ while true; do
     --data)
         # these params must be valid in all cases
         arg_fqdn=$(echo "$2" | $json fqdn)
+        arg_admin_fqdn=$(echo "$2" | $json adminFqdn)
         arg_zone_name=$(echo "$2" | $json zoneName)
         [[ "${arg_zone_name}" == "" ]] && arg_zone_name="${arg_fqdn}"
 
+        # can be removed after 1.9
         arg_is_custom_domain=$(echo "$2" | $json isCustomDomain)
         [[ "${arg_is_custom_domain}" == "" ]] && arg_is_custom_domain="true"
 
diff --git a/setup/splashpage.sh b/setup/splashpage.sh
index 354f62d0d..88d17d947 100755
--- a/setup/splashpage.sh
+++ b/setup/splashpage.sh
@@ -18,8 +18,7 @@ fi
 source "${script_dir}/argparser.sh" "$@" # this injects the arg_* variables used below
 
 # keep this is sync with config.js appFqdn()
-admin_fqdn=$([[ "${arg_is_custom_domain}" == "true" ]] && echo "${arg_admin_location}.${arg_fqdn}" ||  echo "${arg_admin_location}-${arg_fqdn}")
-admin_origin="https://${admin_fqdn}"
+admin_origin="https://${arg_admin_fqdn}"
 
 # copy the website
 rm -rf "${SETUP_WEBSITE_DIR}" && mkdir -p "${SETUP_WEBSITE_DIR}"
@@ -37,7 +36,7 @@ if [[ "${arg_retire_reason}" != "" || "${existing_infra}" != "${current_infra}"
 else
     echo "Show progress bar only on admin domain for normal update"
     ${box_src_dir}/node_modules/.bin/ejs-cli -f "${script_dir}/start/nginx/appconfig.ejs" \
-        -O "{ \"vhost\": \"${admin_fqdn}\", \"adminOrigin\": \"${admin_origin}\", \"endpoint\": \"splash\", \"sourceDir\": \"${SETUP_WEBSITE_DIR}\", \"certFilePath\": \"cert/host.cert\", \"keyFilePath\": \"cert/host.key\", \"xFrameOptions\": \"SAMEORIGIN\", \"robotsTxtQuoted\": null, \"hasIPv6\": false }" > "${PLATFORM_DATA_DIR}/nginx/applications/admin.conf"
+        -O "{ \"vhost\": \"${arg_admin_fqdn}\", \"adminOrigin\": \"${admin_origin}\", \"endpoint\": \"splash\", \"sourceDir\": \"${SETUP_WEBSITE_DIR}\", \"certFilePath\": \"cert/host.cert\", \"keyFilePath\": \"cert/host.key\", \"xFrameOptions\": \"SAMEORIGIN\", \"robotsTxtQuoted\": null, \"hasIPv6\": false }" > "${PLATFORM_DATA_DIR}/nginx/applications/admin.conf"
 fi
 
 if [[ "${arg_retire_reason}" == "migrate" ]]; then
diff --git a/setup/start.sh b/setup/start.sh
index 15adf671b..5375c169a 100755
--- a/setup/start.sh
+++ b/setup/start.sh
@@ -206,6 +206,13 @@ cd "${BOX_SRC_DIR}"
 BOX_ENV=cloudron DATABASE_URL=mysql://root:${mysql_root_password}@127.0.0.1/box "${BOX_SRC_DIR}/node_modules/.bin/db-migrate" up
 EOF
 
+if [[ -z "${arg_admin_fqdn:-}" ]]; then
+    # can be removed after 1.9
+    admin_fqdn=$([[ "${arg_is_custom_domain}" == "true" ]] && echo "${arg_admin_location}.${arg_fqdn}" ||  echo "${arg_admin_location}-${arg_fqdn}")
+else
+    admin_fqdn="${arg_admin_fqdn}"
+fi
+
 echo "==> Creating cloudron.conf"
 cat > "${CONFIG_DIR}/cloudron.conf" <<CONF_END
 {
@@ -214,9 +221,9 @@ cat > "${CONFIG_DIR}/cloudron.conf" <<CONF_END
     "apiServerOrigin": "${arg_api_server_origin}",
     "webServerOrigin": "${arg_web_server_origin}",
     "fqdn": "${arg_fqdn}",
+    "adminFqdn": "${admin_fqdn}",
     "adminLocation": "${arg_admin_location}",
     "zoneName": "${arg_zone_name}",
-    "isCustomDomain": ${arg_is_custom_domain},
     "provider": "${arg_provider}",
     "isDemo": ${arg_is_demo}
 }
diff --git a/src/caas.js b/src/caas.js
index 2328dd020..829663846 100644
--- a/src/caas.js
+++ b/src/caas.js
@@ -56,7 +56,7 @@ function retire(reason, info, callback) {
 
     var data = {
         apiServerOrigin: config.apiServerOrigin(),
-        isCustomDomain: config.isCustomDomain(),
+        adminFqdn: config.adminFqdn(),
         fqdn: config.fqdn()
     };
     shell.sudo('retire', [ RETIRE_CMD, reason, JSON.stringify(info), JSON.stringify(data) ], callback);
diff --git a/src/cloudron.js b/src/cloudron.js
index 03897cb67..d9f99baf8 100644
--- a/src/cloudron.js
+++ b/src/cloudron.js
@@ -194,7 +194,8 @@ function autoprovision(callback) {
     }, callback);
 }
 
-function dnsSetup(domain, zoneName, provider, dnsConfig, callback) {
+function dnsSetup(adminFqdn, domain, zoneName, provider, dnsConfig, callback) {
+    assert.strictEqual(typeof adminFqdn, 'string');
     assert.strictEqual(typeof domain, 'string');
     assert.strictEqual(typeof zoneName, 'string');
     assert.strictEqual(typeof provider, 'string');
@@ -215,6 +216,8 @@ function dnsSetup(domain, zoneName, provider, dnsConfig, callback) {
             if (error) return callback(new CloudronError(CloudronError.INTERNAL_ERROR, error));
 
             config.setFqdn(domain); // set fqdn only after dns config is valid, otherwise cannot re-setup if we failed
+            config.setAdminFqdn(adminFqdn);
+            config.setAdminLocation('my');
             config.setZoneName(zoneName);
 
             callback();
@@ -452,7 +455,6 @@ function getConfig(callback) {
                 version: config.version(),
                 update: updateChecker.getUpdateInfo(),
                 progress: progress.getAll(),
-                isCustomDomain: config.isCustomDomain(),
                 isDemo: config.isDemo(),
                 region: result.box.region,
                 size: result.box.size,
@@ -722,7 +724,6 @@ function doUpdate(boxUpdateInfo, callback) {
             webServerOrigin: config.webServerOrigin(),
             fqdn: config.fqdn(),
             adminLocation: config.adminLocation(),
-            isCustomDomain: config.isCustomDomain(),
             isDemo: config.isDemo(),
             zoneName: config.zoneName(),
 
diff --git a/src/config.js b/src/config.js
index 5233af5e1..37763cbea 100644
--- a/src/config.js
+++ b/src/config.js
@@ -19,10 +19,11 @@ exports = module.exports = {
     fqdn: fqdn,
     zoneName: zoneName,
     setFqdn: setFqdn,
+    setAdminFqdn: setAdminFqdn,
+    setAdminLocation: setAdminLocation,
     token: token,
     version: version,
     setVersion: setVersion,
-    isCustomDomain: isCustomDomain,
     database: database,
 
     // these values are derived
@@ -76,9 +77,9 @@ function saveSync() {
         apiServerOrigin: data.apiServerOrigin,
         webServerOrigin: data.webServerOrigin,
         fqdn: data.fqdn,
+        adminFqdn: data.adminFqdn,
         zoneName: data.zoneName,
         adminLocation: data.adminLocation,
-        isCustomDomain: data.isCustomDomain,
         provider: data.provider,
         isDemo: data.isDemo
     };
@@ -97,12 +98,12 @@ function _reset(callback) {
 function initConfig() {
     // setup defaults
     data.fqdn = '';
+    data.adminFqdn = '';
     data.zoneName = '';
     data.adminLocation = 'my';
     data.port = 3000;
     data.token = null;
     data.version = null;
-    data.isCustomDomain = true;
     data.apiServerOrigin = null;
     data.webServerOrigin = null;
     data.provider = 'caas';
@@ -184,32 +185,29 @@ function zoneName() {
     return tld.getDomain(fqdn()) || '';
 }
 
-// keep this in sync with start.sh admin.conf generation code
-function appFqdn(app) {
-    assert.strictEqual(typeof app, 'object');
-    assert.strictEqual(typeof app.location, 'string');
-    assert.strictEqual(typeof app.domain, 'string');
-
-    if (app.location === '') return app.domain;
-
-    // caas still has subdomains with a dash
-    return app.location + (isCustomDomain() ? '.' : '-') + app.domain;
-}
-
 function mailLocation() {
     return get('adminLocation'); // not a typo! should be same as admin location until we figure out certificates
 }
 
-function mailFqdn() {
-    return appFqdn({ domain: fqdn(), location: mailLocation() });
+function setAdminLocation(location) {
+    set('adminLocation', location);
 }
 
+
 function adminLocation() {
     return get('adminLocation');
 }
 
+function setAdminFqdn(adminFqdn) {
+    set('adminFqdn', adminFqdn);
+}
+
 function adminFqdn() {
-    return appFqdn({ domain: fqdn(), location: adminLocation() });
+    return get('adminFqdn');
+}
+
+function mailFqdn() {
+    return adminFqdn();
 }
 
 function adminOrigin() {
@@ -236,10 +234,6 @@ function setVersion(version) {
     set('version', version);
 }
 
-function isCustomDomain() {
-    return get('isCustomDomain');
-}
-
 function database() {
     return get('database');
 }
diff --git a/src/domains.js b/src/domains.js
index 4ceee3fb0..a5548f0e6 100644
--- a/src/domains.js
+++ b/src/domains.js
@@ -318,8 +318,9 @@ function setAdmin(domain, callback) {
             if (error) return callback(new DomainError(DomainError.EXTERNAL_ERROR, 'Error setting PTR record:' + error.message));
 
             config.setFqdn(result.domain);
+            config.setAdminLocation('my');
+            config.setAdminFqdn('my.' + result.domain);
             config.setZoneName(result.zoneName);
-            config.set('isCustomDomain', true);
 
             callback();
 
diff --git a/src/routes/cloudron.js b/src/routes/cloudron.js
index bd7b0cc84..4a460488b 100644
--- a/src/routes/cloudron.js
+++ b/src/routes/cloudron.js
@@ -108,11 +108,12 @@ function dnsSetup(req, res, next) {
 
     if (typeof req.body.provider !== 'string') return next(new HttpError(400, 'provider is required'));
     if (typeof req.body.domain !== 'string' || !req.body.domain) return next(new HttpError(400, 'domain is required'));
+    if (typeof req.body.adminFqdn !== 'string' || !req.body.domain) return next(new HttpError(400, 'adminFqdn is required'));
 
     if ('zoneName' in req.body && typeof req.body.zoneName !== 'string') return next(new HttpError(400, 'zoneName must be a string'));
     if (!config || typeof req.body.config !== 'object') return next(new HttpError(400, 'config must be an object'));
 
-    cloudron.dnsSetup(req.body.domain.toLowerCase(), req.body.zoneName || '', req.body.provider, req.body.config, function (error) {
+    cloudron.dnsSetup(req.body.adminFqdn.toLowerCase(), req.body.domain.toLowerCase(), req.body.zoneName || '', req.body.provider, req.body.config, function (error) {
         if (error && error.reason === CloudronError.ALREADY_SETUP) return next(new HttpError(409, error.message));
         if (error && error.reason === CloudronError.BAD_FIELD) return next(new HttpError(400, error.message));
         if (error) return next(new HttpError(500, error));
@@ -185,7 +186,7 @@ function getConfig(req, res, next) {
         if (error) return next(new HttpError(500, error));
 
         if (!req.user.admin) {
-            cloudronConfig = _.pick(cloudronConfig, 'apiServerOrigin', 'webServerOrigin', 'fqdn', 'version', 'progress', 'isCustomDomain', 'isDemo', 'cloudronName', 'provider');
+            cloudronConfig = _.pick(cloudronConfig, 'apiServerOrigin', 'webServerOrigin', 'fqdn', 'adminFqdn', 'version', 'progress', 'isDemo', 'cloudronName', 'provider');
         }
 
         next(new HttpSuccess(200, cloudronConfig));
diff --git a/src/routes/test/cloudron-test.js b/src/routes/test/cloudron-test.js
index 7feac9762..590ee73fc 100644
--- a/src/routes/test/cloudron-test.js
+++ b/src/routes/test/cloudron-test.js
@@ -29,6 +29,7 @@ function setup(done) {
     nock.cleanAll();
     config._reset();
     config.setFqdn('example-cloudron-test.com');
+    config.setAdminFqdn('my.example-cloudron-test.com');
 
     async.series([
         server.start.bind(server),
@@ -240,7 +241,7 @@ describe('Cloudron', function () {
                     expect(result.body.apiServerOrigin).to.eql('http://localhost:6060');
                     expect(result.body.webServerOrigin).to.eql(null);
                     expect(result.body.fqdn).to.eql(config.fqdn());
-                    expect(result.body.isCustomDomain).to.eql(true);
+                    expect(result.body.adminFqdn).to.eql(config.adminFqdn());
                     expect(result.body.progress).to.be.an('object');
                     expect(result.body.update).to.be.an('object');
                     expect(result.body.version).to.eql(config.version());
@@ -265,7 +266,7 @@ describe('Cloudron', function () {
                     expect(result.body.apiServerOrigin).to.eql('http://localhost:6060');
                     expect(result.body.webServerOrigin).to.eql(null);
                     expect(result.body.fqdn).to.eql(config.fqdn());
-                    expect(result.body.isCustomDomain).to.eql(true);
+                    expect(result.body.adminFqdn).to.eql(config.adminFqdn());
                     expect(result.body.progress).to.be.an('object');
                     expect(result.body.update).to.be.an('object');
                     expect(result.body.version).to.eql(config.version());
@@ -290,7 +291,7 @@ describe('Cloudron', function () {
                     expect(result.body.apiServerOrigin).to.eql('http://localhost:6060');
                     expect(result.body.webServerOrigin).to.eql(null);
                     expect(result.body.fqdn).to.eql(config.fqdn());
-                    expect(result.body.isCustomDomain).to.eql(true);
+                    expect(result.body.adminFqdn).to.eql(config.adminFqdn());
                     expect(result.body.progress).to.be.an('object');
                     expect(result.body.version).to.eql(config.version());
                     expect(result.body.cloudronName).to.be.a('string');
diff --git a/src/routes/test/oauth2-test.js b/src/routes/test/oauth2-test.js
index e6bfb109b..91557418a 100644
--- a/src/routes/test/oauth2-test.js
+++ b/src/routes/test/oauth2-test.js
@@ -296,6 +296,7 @@ describe('OAuth2', function () {
         function setup(done) {
             config._reset();
             config.setFqdn(APP_0.domain);
+            config.setAdminFqdn('my.' + APP_0.domain);
 
             async.series([
                 server.start,
diff --git a/src/routes/test/settings-test.js b/src/routes/test/settings-test.js
index 2def15b40..68e5336d9 100644
--- a/src/routes/test/settings-test.js
+++ b/src/routes/test/settings-test.js
@@ -29,6 +29,7 @@ var token = null;
 function setup(done) {
     config._reset();
     config.setFqdn('example-settings-test.com');
+    config.setAdminFqdn('my.example-settings-test.com');
     config.set('provider', 'caas');
 
     async.series([
diff --git a/src/test/apps-test.js b/src/test/apps-test.js
index 148b065e7..71b45e5ea 100644
--- a/src/test/apps-test.js
+++ b/src/test/apps-test.js
@@ -132,6 +132,7 @@ describe('Apps', function () {
         config._reset();
 
         config.setFqdn(DOMAIN_0.domain);
+        config.setAdminFqdn('my.' + DOMAIN_0.domain);
 
         async.series([
             database.initialize,
@@ -161,7 +162,7 @@ describe('Apps', function () {
 
     describe('validateHostname', function () {
         it('does not allow admin subdomain', function () {
-            expect(apps._validateHostname('my', 'example.com', 'my.example.com')).to.be.an(Error);
+            expect(apps._validateHostname('my', DOMAIN_0.domain, 'my.' + DOMAIN_0.domain)).to.be.an(Error);
         });
 
         it('cannot have >63 length subdomains', function () {
diff --git a/src/test/config-test.js b/src/test/config-test.js
index eb4e3bb2f..19842de2e 100644
--- a/src/test/config-test.js
+++ b/src/test/config-test.js
@@ -31,8 +31,8 @@ describe('config', function () {
     });
 
     it('did set default values', function () {
-        expect(config.isCustomDomain()).to.equal(true);
         expect(config.fqdn()).to.equal('');
+        expect(config.adminFqdn()).to.equal('');
         expect(config.zoneName()).to.equal('');
         expect(config.adminLocation()).to.equal('my');
     });
@@ -63,20 +63,20 @@ describe('config', function () {
 
     it('uses dotted locations with custom domain', function () {
         config.setFqdn('example.com');
-        config.set('isCustomDomain', true);
+        config.setAdminFqdn('my.example.com');
 
-        expect(config.isCustomDomain()).to.equal(true);
         expect(config.fqdn()).to.equal('example.com');
+        expect(config.adminFqdn()).to.equal('my.example.com');
         expect(config.adminOrigin()).to.equal('https://my.example.com');
         expect(config.zoneName()).to.equal('example.com');
     });
 
     it('uses hyphen locations with non-custom domain', function () {
         config.setFqdn('test.example.com');
-        config.set('isCustomDomain', false);
+        config.setAdminFqdn('my-test.example.com');
 
-        expect(config.isCustomDomain()).to.equal(false);
         expect(config.fqdn()).to.equal('test.example.com');
+        expect(config.adminLocation()).to.equal('my');
         expect(config.adminOrigin()).to.equal('https://my-test.example.com');
         expect(config.zoneName()).to.equal('example.com');
     });
diff --git a/webadmin/src/js/client.js b/webadmin/src/js/client.js
index 15b56be7f..f2b3e0200 100644
--- a/webadmin/src/js/client.js
+++ b/webadmin/src/js/client.js
@@ -737,6 +737,7 @@ angular.module('Application').service('Client', ['$http', '$interval', 'md5', 'N
     Client.prototype.setupDnsConfig = function (domain, zoneName, provider, dnsConfig, callback) {
         var data = {
             domain: domain,
+            adminFqdn: 'my.' + domain,
             zoneName: zoneName,
             provider: provider,
             config: dnsConfig