diff --git a/modules/backend/src/main/scala/sharry/backend/auth/AuthConfig.scala b/modules/backend/src/main/scala/sharry/backend/auth/AuthConfig.scala
index 6d6df2c5..520246c4 100644
--- a/modules/backend/src/main/scala/sharry/backend/auth/AuthConfig.scala
+++ b/modules/backend/src/main/scala/sharry/backend/auth/AuthConfig.scala
@@ -10,6 +10,7 @@ case class AuthConfig(
     http: AuthConfig.Http,
     httpBasic: AuthConfig.HttpBasic,
     command: AuthConfig.Command,
+    proxy: AuthConfig.Proxy,
     internal: AuthConfig.Internal,
     oauth: Seq[AuthConfig.OAuth]
 ) {
@@ -17,12 +18,29 @@ case class AuthConfig(
   def isOAuthOnly: Boolean =
     fixed.disabled && http.disabled &&
       httpBasic.disabled && command.disabled &&
-      internal.disabled && oauth.nonEmpty
+      internal.disabled && proxy.disabled && oauth.exists(_.enabled)
 
+  def isProxyAuthOnly: Boolean =
+    fixed.disabled && http.disabled &&
+      httpBasic.disabled && command.disabled &&
+      internal.disabled && !oauth.exists(_.enabled) && proxy.enabled
+
+  def isAutoLogin: Boolean =
+    fixed.disabled && http.disabled &&
+      httpBasic.disabled && command.disabled &&
+      internal.disabled && (oauth.exists(_.enabled) || proxy.enabled)
 }
 
 object AuthConfig {
 
+  final case class Proxy(
+      enabled: Boolean,
+      userHeader: String,
+      emailHeader: Option[String]
+  ) {
+    def disabled = !enabled
+  }
+
   case class Fixed(enabled: Boolean, user: Ident, password: Password, order: Int) {
     def disabled = !enabled
   }
diff --git a/modules/backend/src/test/scala/sharry/backend/auth/LoginModuleTest.scala b/modules/backend/src/test/scala/sharry/backend/auth/LoginModuleTest.scala
index 6637b667..2829b2df 100644
--- a/modules/backend/src/test/scala/sharry/backend/auth/LoginModuleTest.scala
+++ b/modules/backend/src/test/scala/sharry/backend/auth/LoginModuleTest.scala
@@ -26,6 +26,7 @@ class LoginModuleTest extends FunSuite {
     AuthConfig.Http(true, LenientUri.unsafe("http://test.com"), "GET", "", "", 2),
     AuthConfig.HttpBasic(true, LenientUri.unsafe("http://test.com"), "GET", 3),
     AuthConfig.Command(true, Seq.empty, 0, 4),
+    AuthConfig.Proxy(false, "", None),
     AuthConfig.Internal(true, 5),
     Seq.empty
   )
diff --git a/modules/microsite/docs/doc/configure.md b/modules/microsite/docs/doc/configure.md
index 3ad3d022..6b63344d 100644
--- a/modules/microsite/docs/doc/configure.md
+++ b/modules/microsite/docs/doc/configure.md
@@ -449,6 +449,23 @@ The internal login module simply authenticates against the sharry
 database. If it is disabled, you should disable signup, too, because those
 user won't be authenticated.
 
+#### Proxy
+
+The `proxy` option allows automatically authenticate users by trusting
+specific request headers. The configured headers of the login request
+to `open/auth/proxy` are read and a user account is created if
+missing. Be aware that sharry blindly trusts these headers.
+
+```
+proxy {
+  enabled = false
+  user-header = "X-Valid-User"
+  email-header = "X-User-Email"
+}
+```
+
+The webapp automatically logs the user in, if the auth configuration
+only consists of proxy auth and nothing else.
 
 #### OAuth
 
diff --git a/modules/restapi/src/main/resources/sharry-openapi.yml b/modules/restapi/src/main/resources/sharry-openapi.yml
index a02fb21c..dfdf5481 100644
--- a/modules/restapi/src/main/resources/sharry-openapi.yml
+++ b/modules/restapi/src/main/resources/sharry-openapi.yml
@@ -151,6 +151,20 @@ paths:
           description: OK
         '403':
           description: Forbidden
+  /open/auth/proxy:
+    post:
+      operationId: "open-auth-proxy"
+      tags: [ Authentication ]
+      summary: Authenticate via request headers
+      description: |
+        When using an authenticating proxy in front, this login route
+        can be used to rely on trusted request headers to perform
+        login.
+      responses:
+        '200':
+          description: Ok
+        '403':
+          description: Forbidden
   /sec/auth/session:
     post:
       operationId: "sec-auth-session"
@@ -1923,6 +1937,9 @@ components:
         - defaultValidity
         - initialTheme
         - oauthAutoRedirect
+        - proxyAuthEnabled
+        - proxyOnly
+        - hideLoginForm
       properties:
         appName:
           type: string
@@ -1990,6 +2007,12 @@ components:
           format: theme
         oauthAutoRedirect:
           type: boolean
+        proxyAuthEnabled:
+          type: boolean
+        proxyOnly:
+          type: boolean
+        hideLoginForm:
+          type: boolean
     OAuthItem:
       description: |
         Information about a configured OAuth provider.
diff --git a/modules/restserver/src/main/resources/reference.conf b/modules/restserver/src/main/resources/reference.conf
index 4fc0a42a..4763a904 100644
--- a/modules/restserver/src/main/resources/reference.conf
+++ b/modules/restserver/src/main/resources/reference.conf
@@ -107,10 +107,11 @@ sharry.restserver {
     # The inital ui theme to use. Can be either 'light' or 'dark'.
     initial-theme = "light"
 
-    # When only OAuth is configured and only a single provider, then
-    # the weapp automatically redirects to its authentication page
-    # skipping the sharry login page. This will also disable the
-    # logout button, since sharry is not in charge anyways.
+    # When only OAuth (or only Proxy Auth) is configured and only a
+    # single provider, then the weapp automatically redirects to its
+    # authentication page skipping the sharry login page. This will
+    # also disable the logout button, since sharry is not in charge
+    # anyways.
     oauth-auto-redirect = true
 
     # A custom html snippet that is rendered into the html head
@@ -265,8 +266,8 @@ sharry.restserver {
           id = "aad"
           name = "Azure AD"
           icon = "fab fa-microsoft"
-          scope = ""
-          authorize-url = "https://login.microsoftonline.com/<your tenant ID>/oauth2/v2.0/authorize?scope=openid"
+          scope = "openid"
+          authorize-url = "https://login.microsoftonline.com/<your tenant ID>/oauth2/v2.0/authorize"
           token-url = "https://login.microsoftonline.com/<your tenant ID>/oauth2/v2.0/token"
           user-url = "https://graph.microsoft.com/oidc/userinfo"
           user-id-key = "email"
@@ -275,6 +276,16 @@ sharry.restserver {
           client-secret = "<your client secret>"
         }
       ]
+
+      # Allows to inspect the request headers for finding already
+      # authorized user name/email. If enabled and during login the
+      # request contains these headers, they will be used to
+      # automatically create accounts.
+      proxy {
+        enabled = false
+        user-header = "X-Valid-User"
+        email-header = "X-User-Email"
+      }
     }
 
     # The database connection.
diff --git a/modules/restserver/src/main/scala/sharry/restserver/routes/InfoRoutes.scala b/modules/restserver/src/main/scala/sharry/restserver/routes/InfoRoutes.scala
index 2993791d..fcc717f9 100644
--- a/modules/restserver/src/main/scala/sharry/restserver/routes/InfoRoutes.scala
+++ b/modules/restserver/src/main/scala/sharry/restserver/routes/InfoRoutes.scala
@@ -76,7 +76,10 @@ object InfoRoutes {
       cfg.aliasMemberEnabled,
       cfg.webapp.defaultValidity,
       cfg.webapp.initialTheme,
-      cfg.webapp.oauthAutoRedirect
+      cfg.webapp.oauthAutoRedirect,
+      cfg.backend.auth.proxy.enabled,
+      cfg.backend.auth.isProxyAuthOnly,
+      cfg.backend.auth.isAutoLogin
     )
   }
 
diff --git a/modules/restserver/src/main/scala/sharry/restserver/routes/LoginRoutes.scala b/modules/restserver/src/main/scala/sharry/restserver/routes/LoginRoutes.scala
index 21026d2e..6caa8fd9 100644
--- a/modules/restserver/src/main/scala/sharry/restserver/routes/LoginRoutes.scala
+++ b/modules/restserver/src/main/scala/sharry/restserver/routes/LoginRoutes.scala
@@ -20,6 +20,7 @@ import org.http4s.circe.CirceEntityEncoder._
 import org.http4s.client.Client
 import org.http4s.dsl.Http4sDsl
 import org.http4s.headers.Location
+import org.typelevel.ci.CIString
 
 object LoginRoutes {
 
@@ -42,6 +43,51 @@ object LoginRoutes {
           resp <- makeResponse(dsl, cfg, req, res, up.account)
         } yield resp
 
+      case req @ POST -> Root / "proxy" =>
+        val unameOpt =
+          req.headers
+            .get(CIString(cfg.backend.auth.proxy.userHeader))
+            .map(_.head.value)
+            .filter(_ => cfg.backend.auth.proxy.enabled)
+
+        val email = cfg.backend.auth.proxy.emailHeader
+          .map(CIString.apply)
+          .flatMap(req.headers.get(_).map(_.head.value))
+
+        def doLogin(userId: Ident) = for {
+          newAcc <- NewAccount.create(userId, AccountSource.Extern, email = email)
+          token <- finalizeLogin(cfg, S)(newAcc)
+          resp <- makeResponse(dsl, cfg, req, LoginResult.ok(token), userId.id)
+        } yield resp
+
+        for {
+          _ <-
+            if (cfg.backend.auth.proxy.disabled)
+              logger.info("Proxy authentication is disabled in the config!")
+            else logger.debug(s"Use proxy authentication: user=$unameOpt, email=$email")
+
+          resp <- unameOpt.map(Ident.apply) match {
+            case None =>
+              makeResponse(
+                dsl,
+                cfg,
+                req,
+                LoginResult.invalidAuth,
+                unameOpt.getOrElse("<no-user-id>")
+              )
+            case Some(Left(err)) =>
+              logger.error(s"Error reading username from header: $err") >>
+                makeResponse(
+                  dsl,
+                  cfg,
+                  req,
+                  LoginResult.invalidAuth,
+                  unameOpt.getOrElse("<no-user-id>")
+                )
+            case Some(Right(userId)) => doLogin(userId)
+          }
+        } yield resp
+
       case req @ GET -> Root / "oauth" / id =>
         findOAuthProvider(cfg, id) match {
           case Some(p) =>
@@ -94,12 +140,7 @@ object LoginRoutes {
               email = u.email
             )
           )
-          acc <- OptionT.liftF(S.account.createIfMissing(newAcc))
-          accId = acc.accountId(None)
-          _ <- OptionT.liftF(S.account.updateLoginStats(accId))
-          token <- OptionT.liftF(
-            AuthToken.user[F](accId, cfg.backend.auth.serverSecret)
-          )
+          token <- OptionT.liftF(finalizeLogin(cfg, S)(newAcc))
         } yield token
 
         val uri = getBaseUrl(cfg, req).withQuery("oauth", "1") / "app" / "login"
@@ -113,6 +154,16 @@ object LoginRoutes {
     }
   }
 
+  private def finalizeLogin[F[_]: Async](cfg: Config, S: BackendApp[F])(
+      newAcc: NewAccount
+  ) =
+    for {
+      acc <- S.account.createIfMissing(newAcc)
+      accId = acc.accountId(None)
+      _ <- S.account.updateLoginStats(accId)
+      token <- AuthToken.user[F](accId, cfg.backend.auth.serverSecret)
+    } yield token
+
   private def redirectUri[F[_]](
       cfg: Config,
       req: Request[F],
diff --git a/modules/webapp/src/main/elm/Api.elm b/modules/webapp/src/main/elm/Api.elm
index 1ea48dbc..e9a88768 100644
--- a/modules/webapp/src/main/elm/Api.elm
+++ b/modules/webapp/src/main/elm/Api.elm
@@ -23,6 +23,7 @@ module Api exposing
     , listAliasMember
     , loadAccount
     , login
+    , loginProxy
     , loginSession
     , logout
     , modifyAccount
@@ -537,6 +538,15 @@ login flags up receive =
         }
 
 
+loginProxy : Flags -> (Result Http.Error AuthResult -> msg) -> Cmd msg
+loginProxy flags receive =
+    Http.post
+        { url = flags.config.baseUrl ++ "/api/v2/open/auth/proxy"
+        , body = Http.emptyBody
+        , expect = Http.expectJson receive Api.Model.AuthResult.decoder
+        }
+
+
 logout : Flags -> (Result Http.Error () -> msg) -> Cmd msg
 logout flags receive =
     Http2.authPost
diff --git a/modules/webapp/src/main/elm/App/View.elm b/modules/webapp/src/main/elm/App/View.elm
index 91b0aca2..fbcd1209 100644
--- a/modules/webapp/src/main/elm/App/View.elm
+++ b/modules/webapp/src/main/elm/App/View.elm
@@ -265,13 +265,13 @@ userMenu2 texts model acc =
             , a
                 [ href "#"
                 , class dropdownItem
-                , classList [ ( "disabled", Data.Flags.isOAuthAutoRedirect model.flags ) ]
-                , if Data.Flags.isOAuthAutoRedirect model.flags then
+                , classList [ ( "disabled", Data.Flags.isAutoRedirect model.flags ) ]
+                , if Data.Flags.isAutoRedirect model.flags then
                     class ""
 
                   else
                     onClick Logout
-                , if Data.Flags.isOAuthAutoRedirect model.flags then
+                , if Data.Flags.isAutoRedirect model.flags then
                     title texts.app.logoutOAuth
 
                   else
diff --git a/modules/webapp/src/main/elm/Data/Flags.elm b/modules/webapp/src/main/elm/Data/Flags.elm
index 8e278186..9471f14c 100644
--- a/modules/webapp/src/main/elm/Data/Flags.elm
+++ b/modules/webapp/src/main/elm/Data/Flags.elm
@@ -22,6 +22,16 @@ isOAuthAutoRedirect flags =
     flags.config.oauthAutoRedirect && flags.config.oauthOnly
 
 
+isProxyAutoRedirect : Flags -> Bool
+isProxyAutoRedirect flags =
+    flags.config.oauthAutoRedirect && flags.config.proxyOnly
+
+
+isAutoRedirect : Flags -> Bool
+isAutoRedirect flags =
+    isOAuthAutoRedirect flags || isProxyAutoRedirect flags
+
+
 getToken : Flags -> Maybe String
 getToken flags =
     flags.account
diff --git a/modules/webapp/src/main/elm/Page/Login/Data.elm b/modules/webapp/src/main/elm/Page/Login/Data.elm
index a66a5738..c6ce9029 100644
--- a/modules/webapp/src/main/elm/Page/Login/Data.elm
+++ b/modules/webapp/src/main/elm/Page/Login/Data.elm
@@ -26,6 +26,7 @@ type Msg
     = SetUsername String
     | SetPassword String
     | Authenticate
+    | AuthenticateProxy
     | AuthResp (Result Http.Error AuthResult)
     | Init
     | LangChooseMsg Comp.LanguageChoose.Msg
diff --git a/modules/webapp/src/main/elm/Page/Login/Update.elm b/modules/webapp/src/main/elm/Page/Login/Update.elm
index cc1a3268..09bdf2f1 100644
--- a/modules/webapp/src/main/elm/Page/Login/Update.elm
+++ b/modules/webapp/src/main/elm/Page/Login/Update.elm
@@ -31,6 +31,9 @@ update ( referrer, oauth ) flags key msg model =
                     _ ->
                         ( model, Cmd.none, Nothing )
 
+            else if not oauth && Data.Flags.isProxyAutoRedirect flags && flags.account == Nothing then
+                ( model, Api.loginProxy flags AuthResp, Nothing )
+
             else
                 ( model, Cmd.none, Nothing )
 
@@ -43,6 +46,9 @@ update ( referrer, oauth ) flags key msg model =
         Authenticate ->
             ( model, Api.login flags (UserPass model.username model.password) AuthResp, Nothing )
 
+        AuthenticateProxy ->
+            ( model, Api.loginProxy flags AuthResp, Nothing )
+
         AuthResp (Ok lr) ->
             if lr.success then
                 loginSuccess referrer flags lr model
diff --git a/modules/webapp/src/main/elm/Page/Login/View.elm b/modules/webapp/src/main/elm/Page/Login/View.elm
index fc217a0c..3539a35b 100644
--- a/modules/webapp/src/main/elm/Page/Login/View.elm
+++ b/modules/webapp/src/main/elm/Page/Login/View.elm
@@ -7,7 +7,7 @@ import Data.Flags exposing (Flags)
 import Data.UiTheme exposing (UiTheme)
 import Html exposing (..)
 import Html.Attributes exposing (..)
-import Html.Events exposing (onInput, onSubmit)
+import Html.Events exposing (onClick, onInput, onSubmit)
 import Markdown
 import Messages.LoginPage exposing (Texts)
 import Page exposing (Page(..))
@@ -39,7 +39,7 @@ view texts flags currentTheme model =
                 , onSubmit Authenticate
                 , autocomplete False
                 , classList
-                    [ ( "hidden invisible", flags.config.oauthOnly ) ]
+                    [ ( "hidden invisible", flags.config.hideLoginForm ) ]
                 ]
                 [ div [ class "flex flex-col mt-6" ]
                     [ label
@@ -101,6 +101,7 @@ view texts flags currentTheme model =
 
               else
                 renderOAuthButtons texts flags model
+            , renderProxyAuthButton texts
             , resultMessage texts model
             , renderLangAndSignup texts flags
             ]
@@ -189,6 +190,25 @@ renderOAuthButton texts flags item =
         ]
 
 
+renderProxyAuthButton : Texts -> Html Msg
+renderProxyAuthButton texts =
+    div
+        [ class "flex flex-row space-x-2 flex-wrap items-center justify-center"
+        ]
+        [ a
+            [ class S.primaryBasicButton
+            , class "mt-1"
+            , href "#"
+            , onClick AuthenticateProxy
+            ]
+            [ i [ class "fa fa-right-to-bracket" ] []
+            , span [ class "ml-2" ]
+                [ text texts.loginButton
+                ]
+            ]
+        ]
+
+
 resultMessage : Texts -> Model -> Html Msg
 resultMessage texts model =
     case model.result of