diff --git a/docker/nginx/conf.d.templates/server.account.conf b/docker/nginx/conf.d.templates/server.account.conf
index 0de88c03..40f60f9b 100644
--- a/docker/nginx/conf.d.templates/server.account.conf
+++ b/docker/nginx/conf.d.templates/server.account.conf
@@ -9,6 +9,9 @@
 	server {
 		server_name account.{{PORTAL_DOMAIN}}; # example: account.siasky.net
 
+		set_by_lua_block $skynet_portal_domain { return "{{PORTAL_DOMAIN}}" }
+		set_by_lua_block $skynet_server_domain { return "{{SERVER_DOMAIN}}" == "" and "{{PORTAL_DOMAIN}}" or "{{SERVER_DOMAIN}}" }
+
 		ssl_certificate     /data/caddy/caddy/certificates/acme-v02.api.letsencrypt.org-directory/wildcard_.{{PORTAL_DOMAIN}}/wildcard_.{{PORTAL_DOMAIN}}.crt;
 		ssl_certificate_key	/data/caddy/caddy/certificates/acme-v02.api.letsencrypt.org-directory/wildcard_.{{PORTAL_DOMAIN}}/wildcard_.{{PORTAL_DOMAIN}}.key;
 
@@ -31,6 +34,9 @@
 		ssl_certificate     /data/caddy/caddy/certificates/acme-v02.api.letsencrypt.org-directory/wildcard_.{{SERVER_DOMAIN}}/wildcard_.{{SERVER_DOMAIN}}.crt;
 		ssl_certificate_key	/data/caddy/caddy/certificates/acme-v02.api.letsencrypt.org-directory/wildcard_.{{SERVER_DOMAIN}}/wildcard_.{{SERVER_DOMAIN}}.key;
 
+		set_by_lua_block $skynet_portal_domain { return "{{SERVER_DOMAIN}}" }
+		set_by_lua_block $skynet_server_domain { return "{{SERVER_DOMAIN}}" }
+
 		include /etc/nginx/conf.d/server/server.account;
 		
 		set_by_lua_block $server_alias { return string.match("{{SERVER_DOMAIN}}", "^([^.]+)") }
diff --git a/docker/nginx/conf.d.templates/server.api.conf b/docker/nginx/conf.d.templates/server.api.conf
index 1adb58c1..84c6b28d 100644
--- a/docker/nginx/conf.d.templates/server.api.conf
+++ b/docker/nginx/conf.d.templates/server.api.conf
@@ -8,6 +8,9 @@ server {
 server {
 	server_name {{PORTAL_DOMAIN}}; # example: siasky.net
 
+	set_by_lua_block $skynet_portal_domain { return "{{PORTAL_DOMAIN}}" }
+	set_by_lua_block $skynet_server_domain { return "{{SERVER_DOMAIN}}" == "" and "{{PORTAL_DOMAIN}}" or "{{SERVER_DOMAIN}}" }
+
 	ssl_certificate     /data/caddy/caddy/certificates/acme-v02.api.letsencrypt.org-directory/{{PORTAL_DOMAIN}}/{{PORTAL_DOMAIN}}.crt;
 	ssl_certificate_key	/data/caddy/caddy/certificates/acme-v02.api.letsencrypt.org-directory/{{PORTAL_DOMAIN}}/{{PORTAL_DOMAIN}}.key;
 
@@ -30,6 +33,9 @@ server {
 	ssl_certificate     /data/caddy/caddy/certificates/acme-v02.api.letsencrypt.org-directory/{{SERVER_DOMAIN}}/{{SERVER_DOMAIN}}.crt;
 	ssl_certificate_key	/data/caddy/caddy/certificates/acme-v02.api.letsencrypt.org-directory/{{SERVER_DOMAIN}}/{{SERVER_DOMAIN}}.key;
 
+	set_by_lua_block $skynet_portal_domain { return "{{SERVER_DOMAIN}}" }
+	set_by_lua_block $skynet_server_domain { return "{{SERVER_DOMAIN}}" }
+
 	include /etc/nginx/conf.d/server/server.api;
 	
 	set_by_lua_block $server_alias { return string.match("{{SERVER_DOMAIN}}", "^([^.]+)") }
diff --git a/docker/nginx/conf.d.templates/server.hns.conf b/docker/nginx/conf.d.templates/server.hns.conf
index a40427f1..94ce1aa8 100644
--- a/docker/nginx/conf.d.templates/server.hns.conf
+++ b/docker/nginx/conf.d.templates/server.hns.conf
@@ -8,6 +8,9 @@ server {
 server {
 	server_name *.hns.{{PORTAL_DOMAIN}}; # example: *.hns.siasky.net
 	
+	set_by_lua_block $skynet_portal_domain { return "{{PORTAL_DOMAIN}}" }
+	set_by_lua_block $skynet_server_domain { return "{{SERVER_DOMAIN}}" == "" and "{{PORTAL_DOMAIN}}" or "{{SERVER_DOMAIN}}" }
+
 	ssl_certificate     /data/caddy/caddy/certificates/acme-v02.api.letsencrypt.org-directory/wildcard_.hns.{{PORTAL_DOMAIN}}/wildcard_.hns.{{PORTAL_DOMAIN}}.crt;
 	ssl_certificate_key	/data/caddy/caddy/certificates/acme-v02.api.letsencrypt.org-directory/wildcard_.hns.{{PORTAL_DOMAIN}}/wildcard_.hns.{{PORTAL_DOMAIN}}.key;
     
@@ -30,6 +33,9 @@ server {
 	
 	ssl_certificate     /data/caddy/caddy/certificates/acme-v02.api.letsencrypt.org-directory/wildcard_.hns.{{SERVER_DOMAIN}}/wildcard_.hns.{{SERVER_DOMAIN}}.crt;
 	ssl_certificate_key	/data/caddy/caddy/certificates/acme-v02.api.letsencrypt.org-directory/wildcard_.hns.{{SERVER_DOMAIN}}/wildcard_.hns.{{SERVER_DOMAIN}}.key;
+
+	set_by_lua_block $skynet_portal_domain { return "{{SERVER_DOMAIN}}" }
+	set_by_lua_block $skynet_server_domain { return "{{SERVER_DOMAIN}}" }
     
 	proxy_set_header Host {{SERVER_DOMAIN}};
 	include /etc/nginx/conf.d/server/server.hns;
diff --git a/docker/nginx/conf.d.templates/server.skylink.conf b/docker/nginx/conf.d.templates/server.skylink.conf
index 0cfc2027..0a70044c 100644
--- a/docker/nginx/conf.d.templates/server.skylink.conf
+++ b/docker/nginx/conf.d.templates/server.skylink.conf
@@ -7,6 +7,9 @@ server {
 
 server {
 	server_name *.{{PORTAL_DOMAIN}}; # example: *.siasky.net
+	
+	set_by_lua_block $skynet_portal_domain { return "{{PORTAL_DOMAIN}}" }
+	set_by_lua_block $skynet_server_domain { return "{{SERVER_DOMAIN}}" == "" and "{{PORTAL_DOMAIN}}" or "{{SERVER_DOMAIN}}" }
 
 	ssl_certificate     /data/caddy/caddy/certificates/acme-v02.api.letsencrypt.org-directory/wildcard_.{{PORTAL_DOMAIN}}/wildcard_.{{PORTAL_DOMAIN}}.crt;
 	ssl_certificate_key	/data/caddy/caddy/certificates/acme-v02.api.letsencrypt.org-directory/wildcard_.{{PORTAL_DOMAIN}}/wildcard_.{{PORTAL_DOMAIN}}.key;
@@ -26,6 +29,9 @@ server {
 
 server {
 	server_name *.{{SERVER_DOMAIN}}; # example: *.eu-ger-1.siasky.net
+
+	set_by_lua_block $skynet_portal_domain { return "{{SERVER_DOMAIN}}" }
+	set_by_lua_block $skynet_server_domain { return "{{SERVER_DOMAIN}}" }
 	
 	ssl_certificate     /data/caddy/caddy/certificates/acme-v02.api.letsencrypt.org-directory/wildcard_.{{SERVER_DOMAIN}}/wildcard_.{{SERVER_DOMAIN}}.crt;
 	ssl_certificate_key	/data/caddy/caddy/certificates/acme-v02.api.letsencrypt.org-directory/wildcard_.{{SERVER_DOMAIN}}/wildcard_.{{SERVER_DOMAIN}}.key;
diff --git a/docker/nginx/conf.d/include/location-hns b/docker/nginx/conf.d/include/location-hns
index b0c7322d..62ff9729 100644
--- a/docker/nginx/conf.d/include/location-hns
+++ b/docker/nginx/conf.d/include/location-hns
@@ -81,8 +81,8 @@ proxy_pass https://127.0.0.1/$skylink$path$is_args$args;
 
 # in case siad returns location header, we need to replace the skylink with the domain name
 header_filter_by_lua_block {
-    ngx.header["Skynet-Portal-Api"] = ngx.var.scheme .. "://" .. os.getenv("PORTAL_DOMAIN")
-    ngx.header["Skynet-Server-Api"] = ngx.var.scheme .. "://" .. os.getenv("SERVER_DOMAIN")
+    ngx.header["Skynet-Portal-Api"] = ngx.var.scheme .. "://" .. ngx.var.skynet_portal_domain
+    ngx.header["Skynet-Server-Api"] = ngx.var.scheme .. "://" .. ngx.var.skynet_server_domain
 
     if ngx.header.location then
         -- match location redirect part after the skylink
diff --git a/docker/nginx/conf.d/include/location-skylink b/docker/nginx/conf.d/include/location-skylink
index db3a7b86..da4727c7 100644
--- a/docker/nginx/conf.d/include/location-skylink
+++ b/docker/nginx/conf.d/include/location-skylink
@@ -85,8 +85,8 @@ access_by_lua_block {
 }
 
 header_filter_by_lua_block {
-    ngx.header["Skynet-Portal-Api"] = ngx.var.scheme .. "://" .. os.getenv("PORTAL_DOMAIN")
-    ngx.header["Skynet-Server-Api"] = ngx.var.scheme .. "://" .. os.getenv("SERVER_DOMAIN")
+    ngx.header["Skynet-Portal-Api"] = ngx.var.scheme .. "://" .. ngx.var.skynet_portal_domain
+    ngx.header["Skynet-Server-Api"] = ngx.var.scheme .. "://" .. ngx.var.skynet_server_domain
 
     -- the block below only makes sense if we are using nginx cache
     if not ngx.var.skyd_disk_cache_enabled then
diff --git a/docker/nginx/conf.d/server/server.api b/docker/nginx/conf.d/server/server.api
index 58648a9b..335a3c8b 100644
--- a/docker/nginx/conf.d/server/server.api
+++ b/docker/nginx/conf.d/server/server.api
@@ -247,8 +247,7 @@ location /skynet/tus {
     proxy_set_header X-Forwarded-Proto $scheme;
 
     # rewrite proxy request to use correct host uri from env variable (required to return correct location header)
-    set_by_lua_block $server_domain { return os.getenv("SERVER_DOMAIN") }
-    proxy_redirect $scheme://$host $scheme://$server_domain;
+    proxy_redirect $scheme://$host $scheme://$skynet_server_domain;
 
     # proxy /skynet/tus requests to siad endpoint with all arguments
     proxy_pass http://sia:9980;
@@ -275,8 +274,8 @@ location /skynet/tus {
 
     # extract skylink from base64 encoded upload metadata and assign to a proper header
     header_filter_by_lua_block {
-        ngx.header["Skynet-Portal-Api"] = ngx.var.scheme .. "://" .. os.getenv("PORTAL_DOMAIN")
-        ngx.header["Skynet-Server-Api"] = ngx.var.scheme .. "://" .. os.getenv("SERVER_DOMAIN")
+        ngx.header["Skynet-Portal-Api"] = ngx.var.scheme .. "://" .. ngx.var.skynet_portal_domain
+        ngx.header["Skynet-Server-Api"] = ngx.var.scheme .. "://" .. ngx.var.skynet_server_domain
 
         if ngx.header["Upload-Metadata"] then
             local encodedSkylink = string.match(ngx.header["Upload-Metadata"], "Skylink ([^,?]+)")
@@ -310,8 +309,8 @@ location /skynet/metadata {
     include /etc/nginx/conf.d/include/portal-access-check;
 
     header_filter_by_lua_block {
-        ngx.header["Skynet-Portal-Api"] = ngx.var.scheme .. "://" .. os.getenv("PORTAL_DOMAIN")
-        ngx.header["Skynet-Server-Api"] = ngx.var.scheme .. "://" .. os.getenv("SERVER_DOMAIN")
+        ngx.header["Skynet-Portal-Api"] = ngx.var.scheme .. "://" .. ngx.var.skynet_portal_domain
+        ngx.header["Skynet-Server-Api"] = ngx.var.scheme .. "://" .. ngx.var.skynet_server_domain
     }
 
     proxy_set_header User-Agent: Sia-Agent;
@@ -323,8 +322,8 @@ location /skynet/resolve {
     include /etc/nginx/conf.d/include/portal-access-check;
 
     header_filter_by_lua_block {
-        ngx.header["Skynet-Portal-Api"] = ngx.var.scheme .. "://" .. os.getenv("PORTAL_DOMAIN")
-        ngx.header["Skynet-Server-Api"] = ngx.var.scheme .. "://" .. os.getenv("SERVER_DOMAIN")
+        ngx.header["Skynet-Portal-Api"] = ngx.var.scheme .. "://" .. ngx.var.skynet_portal_domain
+        ngx.header["Skynet-Server-Api"] = ngx.var.scheme .. "://" .. ngx.var.skynet_server_domain
     }
 
     proxy_set_header User-Agent: Sia-Agent;
diff --git a/docker/nginx/nginx.conf b/docker/nginx/nginx.conf
index 64397630..7f43d192 100644
--- a/docker/nginx/nginx.conf
+++ b/docker/nginx/nginx.conf
@@ -95,8 +95,8 @@ http {
 
     # include skynet-portal-api and skynet-server-api header on every request
     header_filter_by_lua_block {
-        ngx.header["Skynet-Portal-Api"] = ngx.var.scheme .. "://" .. os.getenv("PORTAL_DOMAIN")
-        ngx.header["Skynet-Server-Api"] = ngx.var.scheme .. "://" .. os.getenv("SERVER_DOMAIN")
+        ngx.header["Skynet-Portal-Api"] = ngx.var.scheme .. "://" .. ngx.var.skynet_portal_domain
+        ngx.header["Skynet-Server-Api"] = ngx.var.scheme .. "://" .. ngx.var.skynet_server_domain
     }
 
     # ratelimit specified IPs