diff --git a/nixos/modules/services/web-servers/caddy/vhost-options.nix b/nixos/modules/services/web-servers/caddy/vhost-options.nix
index 04feb6dc66c67..73ef4b87ee528 100644
--- a/nixos/modules/services/web-servers/caddy/vhost-options.nix
+++ b/nixos/modules/services/web-servers/caddy/vhost-options.nix
@@ -58,7 +58,7 @@ in
     logFormat = mkOption {
       type = types.lines;
       default = ''
-        output file ${cfg.logDir}/access-${config.hostName}.log
+        output file ${cfg.logDir}/access-${lib.replaceStrings [ "/" " " ] [ "_" "_" ] config.hostName}.log
       '';
       defaultText = ''
         output file ''${config.services.caddy.logDir}/access-''${hostName}.log
diff --git a/nixos/tests/caddy.nix b/nixos/tests/caddy.nix
index 36d0051cf0370..71d73465d0887 100644
--- a/nixos/tests/caddy.nix
+++ b/nixos/tests/caddy.nix
@@ -41,6 +41,11 @@ import ./make-test-python.nix (
               "http://localhost:8081" = { };
             };
           };
+          specialisation.multiple-hostnames.configuration = {
+            services.caddy.virtualHosts = {
+              "http://localhost:8080 http://localhost:8081" = { };
+            };
+          };
           specialisation.rfc42.configuration = {
             services.caddy.settings = {
               apps.http.servers.default = {
@@ -70,7 +75,7 @@ import ./make-test-python.nix (
             services.caddy = {
               package = pkgs.caddy.withPlugins {
                 plugins = [ "github.com/caddyserver/replace-response@v0.0.0-20241211194404-3865845790a7" ];
-                hash = "sha256-zgMdtOJbmtRSfTlrrg8njr11in2C7OAXLB+34V23jek=";
+                hash = "sha256-BorJJWICgAWU7DrpDZJWifMnIYtGWldt/4S1VELwGJI=";
               };
               configFile = pkgs.writeText "Caddyfile" ''
                 {
@@ -93,6 +98,7 @@ import ./make-test-python.nix (
         explicitConfigFile = "${nodes.webserver.system.build.toplevel}/specialisation/explicit-config-file";
         justReloadSystem = "${nodes.webserver.system.build.toplevel}/specialisation/config-reload";
         multipleConfigs = "${nodes.webserver.system.build.toplevel}/specialisation/multiple-configs";
+        multipleHostnames = "${nodes.webserver.system.build.toplevel}/specialisation/multiple-hostnames";
         rfc42Config = "${nodes.webserver.system.build.toplevel}/specialisation/rfc42";
         withPluginsConfig = "${nodes.webserver.system.build.toplevel}/specialisation/with-plugins";
       in
@@ -117,6 +123,13 @@ import ./make-test-python.nix (
             webserver.wait_for_open_port(8080)
             webserver.wait_for_open_port(8081)
 
+        with subtest("a virtual host with multiple hostnames works"):
+            webserver.succeed(
+                "${multipleHostnames}/bin/switch-to-configuration test >&2"
+            )
+            webserver.wait_for_open_port(8080)
+            webserver.wait_for_open_port(8081)
+
         with subtest("rfc42 settings config"):
             webserver.succeed(
                 "${rfc42Config}/bin/switch-to-configuration test >&2"