diff --git a/cmd/anubis/main.go b/cmd/anubis/main.go
index 59dd56f9..5ccdcc01 100644
--- a/cmd/anubis/main.go
+++ b/cmd/anubis/main.go
@@ -68,7 +68,7 @@ var (
 	slogLevel                = flag.String("slog-level", "INFO", "logging level (see https://pkg.go.dev/log/slog#hdr-Levels)")
 	stripBasePrefix          = flag.Bool("strip-base-prefix", false, "if true, strips the base prefix from requests forwarded to the target server")
 	target                   = flag.String("target", "http://localhost:3923", "target to reverse proxy to, set to an empty string to disable proxying when only using auth request")
-	targetSNI                = flag.String("target-sni", "", "if set, the value of the TLS handshake hostname when forwarding requests to the target")
+	targetSNI                = flag.String("target-sni", "", "if set, TLS handshake hostname when forwarding requests to the target, if set to auto, use Host header")
 	targetHost               = flag.String("target-host", "", "if set, the value of the Host header when forwarding requests to the target")
 	targetInsecureSkipVerify = flag.Bool("target-insecure-skip-verify", false, "if true, skips TLS validation for the backend")
 	targetDisableKeepAlive   = flag.Bool("target-disable-keepalive", false, "if true, disables HTTP keep-alive for the backend")
@@ -83,6 +83,7 @@ var (
 	versionFlag              = flag.Bool("version", false, "print Anubis version")
 	publicUrl                = flag.String("public-url", "", "the externally accessible URL for this Anubis instance, used for constructing redirect URLs (e.g., for forwardAuth).")
 	xffStripPrivate          = flag.Bool("xff-strip-private", true, "if set, strip private addresses from X-Forwarded-For")
+	customRealIPHeader      = flag.String("custom-real-ip-header", "", "if set, read remote IP from header of this name (in case your environment doesn't set X-Real-IP header)")
 
 	thothInsecure        = flag.Bool("thoth-insecure", false, "if set, connect to Thoth over plain HTTP/2, don't enable this unless support told you to")
 	thothURL             = flag.String("thoth-url", "", "if set, URL for Thoth, the IP reputation database for Anubis")
@@ -235,23 +236,28 @@ func makeReverseProxy(target string, targetSNI string, targetHost string, insecu
 
 	if insecureSkipVerify || targetSNI != "" {
 		transport.TLSClientConfig = &tls.Config{}
-		if insecureSkipVerify {
-			slog.Warn("TARGET_INSECURE_SKIP_VERIFY is set to true, TLS certificate validation will not be performed", "target", target)
-			transport.TLSClientConfig.InsecureSkipVerify = true
-		}
-		if targetSNI != "" {
-			transport.TLSClientConfig.ServerName = targetSNI
-		}
+	}
+	if insecureSkipVerify {
+		slog.Warn("TARGET_INSECURE_SKIP_VERIFY is set to true, TLS certificate validation will not be performed", "target", target)
+		transport.TLSClientConfig.InsecureSkipVerify = true
+	}
+	if targetSNI != "" && targetSNI != "auto" {
+		transport.TLSClientConfig.ServerName = targetSNI
 	}
 
 	rp := httputil.NewSingleHostReverseProxy(targetUri)
 	rp.Transport = transport
 
-	if targetHost != "" {
+	if targetHost != "" || targetSNI == "auto" {
 		originalDirector := rp.Director
 		rp.Director = func(req *http.Request) {
 			originalDirector(req)
-			req.Host = targetHost
+			if targetHost != "" {
+				req.Host = targetHost
+			}
+			if targetSNI == "auto" {
+				transport.TLSClientConfig.ServerName = req.Host
+			}
 		}
 	}
 
@@ -460,6 +466,7 @@ func main() {
 
 	var h http.Handler
 	h = s
+	h = internal.CustomRealIPHeader(*customRealIPHeader, h)
 	h = internal.RemoteXRealIP(*useRemoteAddress, *bindNetwork, h)
 	h = internal.XForwardedForToXRealIP(h)
 	h = internal.XForwardedForUpdate(*xffStripPrivate, h)
diff --git a/docs/docs/CHANGELOG.md b/docs/docs/CHANGELOG.md
index 8f91735d..f5f54d18 100644
--- a/docs/docs/CHANGELOG.md
+++ b/docs/docs/CHANGELOG.md
@@ -13,6 +13,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 <!-- This changes the project to: -->
 
+- Add `-custom-real-ip-header` flag to get the original request IP from a different header than `x-real-ip`.
 - Add `contentLength` variable to bot expressions.
 - Add `COOKIE_SAME_SITE_MODE` to force anubis cookies SameSite value, and downgrade automatically from `None` to `Lax` if cookie is insecure.
 - Fix lock convoy problem in decaymap ([#1103](https://github.com/TecharoHQ/anubis/issues/1103)).
@@ -29,6 +30,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Randomly use the Refresh header instead of the meta refresh tag in the metarefresh challenge.
 - Update OpenRC service to truncate the runtime directory before starting Anubis.
 - Allow multiple consecutive slashes in a row in application paths ([#754](https://github.com/TecharoHQ/anubis/issues/754)).
+- Add option to set `targetSNI` to special keyword 'auto' to indicate that it should be automatically set to the request Host name ([424](https://github.com/TecharoHQ/anubis/issues/424)).
 
 ### Bug Fixes
 
diff --git a/docs/docs/admin/caveats-xff.mdx b/docs/docs/admin/caveats-xff.mdx
index 655534f3..54b04f5e 100644
--- a/docs/docs/admin/caveats-xff.mdx
+++ b/docs/docs/admin/caveats-xff.mdx
@@ -20,6 +20,8 @@ Upstream: X-Forwarded-For: CF_IP
 
 As a workaround, you should configure your web server to parse an alternative source (such as `CF-Connecting-IP`), or pre-process the incoming `X-Forwarded-For` with your web server to ensure it only contains the real client IP address, then pass it to Anubis as `X-Forwarded-For`.
 
+If you do not control the web server upstream of Anubis, the `custom-real-ip-header` command line flag accepts a header value that Anubis will read the real client IP address from. Anubis will set the `X-Real-IP` header to the IP address found in the custom header.
+
 The `X-Real-IP` header will be automatically inferred from `X-Forwarded-For` if not set, setting it explicitly is not necessary as long as `X-Forwarded-For` contains only the real client IP. However setting it explicitly can eliminate spoofed values if your web server doesn't set this.
 
 See [Cloudflare](environments/cloudflare.mdx) for an example configuration.
diff --git a/docs/docs/admin/installation.mdx b/docs/docs/admin/installation.mdx
index b82fe7b9..0edd65d7 100644
--- a/docs/docs/admin/installation.mdx
+++ b/docs/docs/admin/installation.mdx
@@ -76,6 +76,7 @@ Anubis uses these environment variables for configuration:
 | `COOKIE_DOMAIN`                | unset                   | The domain the Anubis challenge pass cookie should be set to. This should be set to the domain you bought from your registrar (EG: `techaro.lol` if your webapp is running on `anubis.techaro.lol`). See this [stackoverflow explanation of cookies](https://stackoverflow.com/a/1063760) for more information.<br/><br/>Note that unlike `REDIRECT_DOMAINS`, you should never include a port number in this variable.                                                                                                                         |
 | `COOKIE_DYNAMIC_DOMAIN`        | false                   | If set to true, automatically set cookie domain fields based on the hostname of the request. EG: if you are making a request to `anubis.techaro.lol`, the Anubis cookie will be valid for any subdomain of `techaro.lol`.                                                                                                                                                                                                                                                                                                                      |
 | `COOKIE_EXPIRATION_TIME`       | `168h`                  | The amount of time the authorization cookie is valid for.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
+| `CUSTOM_REAL_IP_HEADER`        | unset                   | If set, Anubis will read the client's real IP address from this header, and set it in `X-Real-IP` header.                                                                                                                                                                                                                                                                                                                                                                                                                                      |
 | `COOKIE_PARTITIONED`           | `false`                 | If set to `true`, enables the [partitioned (CHIPS) flag](https://developers.google.com/privacy-sandbox/cookies/chips), meaning that Anubis inside an iframe has a different set of cookies than the domain hosting the iframe.                                                                                                                                                                                                                                                                                                                 |
 | `COOKIE_PREFIX`                | `anubis-cookie`         | The prefix used for browser cookies created by Anubis. Useful for customization or avoiding conflicts with other applications.                                                                                                                                                                                                                                                                                                                                                                                                                 |
 | `COOKIE_SECURE`                | `true`                  | If set to `true`, enables the [Secure flag](https://developer.mozilla.org/en-US/docs/Web/HTTP/Guides/Cookies#block_access_to_your_cookies), meaning that the cookies will only be transmitted over HTTPS. If Anubis is used in an unsecure context (plain HTTP), this will be need to be set to false                                                                                                                                                                                                                                          |
@@ -122,7 +123,7 @@ If you don't know or understand what these settings mean, ignore them. These are
 | `TARGET_DISABLE_KEEPALIVE`    | `false`       | If `true`, disables HTTP keep-alive for connections to the target backend. Useful for backends that don't handle keep-alive properly.                                                                                                                                                                                                                                                           |
 | `TARGET_HOST`                 | unset         | If set, overrides the Host header in requests forwarded to `TARGET`.                                                                                                                                                                                                                                                                                                                            |
 | `TARGET_INSECURE_SKIP_VERIFY` | `false`       | If `true`, skip TLS certificate validation for targets that listen over `https`. If your backend does not listen over `https`, ignore this setting.                                                                                                                                                                                                                                             |
-| `TARGET_SNI`                  | unset         | If set, overrides the TLS handshake hostname in requests forwarded to `TARGET`.                                                                                                                                                                                                                                                                                                                 |
+| `TARGET_SNI`                  | unset         | If set, TLS handshake hostname when forwarding requests to the `TARGET`. If set to auto, use Host header.                                                                                                                                                                                                                                                                                                                 |
 
 </details>
 
diff --git a/internal/headers.go b/internal/headers.go
index 8b478665..21601d24 100644
--- a/internal/headers.go
+++ b/internal/headers.go
@@ -38,6 +38,22 @@ func UnchangingCache(next http.Handler) http.Handler {
 	})
 }
 
+// CustomXRealIPHeader sets the X-Real-IP header to the value of a
+// different header.
+// Used in environments where the upstream proxy sets the request's
+// origin IP in a custom header.
+func CustomRealIPHeader(customRealIPHeaderValue string, next http.Handler) http.Handler {
+	if customRealIPHeaderValue == "" {
+		slog.Debug("skipping middleware, customRealIPHeaderValue is empty")
+		return next
+	}
+
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		r.Header.Set("X-Real-IP", r.Header.Get(customRealIPHeaderValue))
+		next.ServeHTTP(w, r)
+	})
+}
+
 // RemoteXRealIP sets the X-Real-Ip header to the request's real IP if
 // the setting is enabled by the user.
 func RemoteXRealIP(useRemoteAddress bool, bindNetwork string, next http.Handler) http.Handler {
diff --git a/lib/localization/locales/nn.json b/lib/localization/locales/nn.json
index d49396a8..0b0d6eaf 100644
--- a/lib/localization/locales/nn.json
+++ b/lib/localization/locales/nn.json
@@ -13,7 +13,7 @@
   "try_again": "Prøv att",
   "go_home": "Gå heim",
   "contact_webmaster": "eller om du synest at du ikkje burde vera blokkert, venlegast tak kontakt med administratoren på",
-  "connection_security": "Venlegast vent medan vi stadfestar tryggleiken av tilkoplinga di.",
+  "connection_security": "Venlegast vent medan vi stadfester tryggleiken av tilkoplinga di.",
   "javascript_required": "Du lyt diverre slå på JavaScript for å koma deg forbi denne utfordringa. Dette krevst av di KI-selskap har endra sosialkontrakten om korleis nettstadsverting fungerer. Ei ikkje-JS-løysing er i gang med å skapast.",
   "benchmark_requires_js": "JavaScript må vera slegen på for å køyre samanlikningsverktøyet.",
   "difficulty": "Vanskenivå:",
@@ -41,7 +41,7 @@
   "oh_noes": "Å nei!",
   "benchmarking_anubis": "Samanliknar Anubis!",
   "you_are_not_a_bot": "Du er ikkje ein bot!",
-  "making_sure_not_bot": "Stadfestar at du ikkje er ein bot!",
+  "making_sure_not_bot": "Stadfester at du ikkje er ein bot!",
   "celphase": "CELPHASE",
   "js_web_crypto_error": "Nettlesaren din har ikkje eit fungerande web.crypto-element. Ser du dette med ei sikker tilkopling?",
   "js_web_workers_error": "Nettlesaren din støttar ikkje nettarbeidarar (Anubis brukar dette for å unngå å fryse nettlesaren din). Har du eit tillegg som JShelter installert?",
@@ -63,4 +63,4 @@
   "js_calculation_error_msg": "Mislukkast i å rekne utfordring:",
   "missing_required_forwarded_headers": "Manglende nødvendige X-Forwarded-* headers",
   "simplified_explanation": "Dette er eit tiltak mot robotar og vondsinna førespurnader som liknar på ein CAPTCHA. Men i staden for å måtte gjere arbeidet sjølv, får nettlesaren din ei utrekningsoppgåve som han må løyse for å sikre at han er ein gyldig klient. Dette konseptet blir kalla <a href=\"https://en.wikipedia.org/wiki/Proof_of_work\">Arbeidsbevis</a>. Oppgåva blir rekna ut på nokre få sekund, og du får tilgang til nettstaden. Takk for di forståing og tålmod."
-}
\ No newline at end of file
+}