diff --git a/plugin/include/txn_box/Config.h b/plugin/include/txn_box/Config.h
index 79da92b..01ed8ce 100644
--- a/plugin/include/txn_box/Config.h
+++ b/plugin/include/txn_box/Config.h
@@ -131,6 +131,9 @@ class Config {
 
   ~Config();
 
+  swoc::Errata load_file_glob(swoc::TextView pattern, swoc::TextView cfg_key);
+  swoc::Errata load_file(swoc::file::path const& cfg_path, swoc::TextView cfg_key);
+
   /** Parse YAML from @a node to initialize @a this configuration.
    *
    * @param root Root node.
@@ -421,6 +424,29 @@ class Config {
    * @see Extractor::validate
    */
   swoc::Rv<ActiveType> validate(Extractor::Spec &spec);
+
+  // Configuration file tracking.
+  class FileInfo {
+    using self_type = FileInfo;
+  public:
+    using key_type = swoc::TextView;
+
+    FileInfo(key_type key) : _path(key) {}
+
+    // IntrusiveHashMap support.
+    static key_type key_of(self_type *self) { return self->_path; }
+    static bool equal(key_type lhs, key_type rhs) { return lhs == rhs; }
+    static size_t hash_of(key_type key) { return std::hash<std::string_view>()(key); }
+    static self_type *& next_ptr(self_type * self) { return self->_next; }
+    static self_type *& prev_ptr(self_type * self) { return self->_prev; }
+
+  protected:
+    key_type _path; ///< Absolute path to file.
+    self_type * _next = nullptr;
+    self_type * _prev = nullptr;
+  };
+
+  swoc::IntrusiveHashMap<FileInfo> _cfg_files;
 };
 
 inline Hook Config::current_hook() const { return _hook; }
diff --git a/plugin/include/txn_box/Directive.h b/plugin/include/txn_box/Directive.h
index 5db6a9c..59f387d 100644
--- a/plugin/include/txn_box/Directive.h
+++ b/plugin/include/txn_box/Directive.h
@@ -21,16 +21,14 @@
 
 class Context;
 
-/** Base class for directives.
- *
- */
+/// Base class for directives.
 class Directive {
   using self_type = Directive; ///< Self reference type.
   friend Config;
   friend Context;
 
 public:
-  /// Import global value for convienence.
+  /// Import global value for convenience.
   static constexpr swoc::TextView DO_KEY = Global::DO_KEY;
 
   /// Generic handle for all directives.
@@ -45,6 +43,15 @@ class Directive {
    */
   using InstanceLoader = std::function<swoc::Rv<Directive::Handle> (Config& cfg, YAML::Node drtv_node, swoc::TextView const& name, swoc::TextView const& arg, YAML::Node key_value)>;
 
+  /** Functor to do config level initialization.
+   *
+   * @param cfg Configuration object.
+   *
+   * This is called once per directive class when the @c Config instance is initialized. This should
+   * perform any initialization needed for the directive as a type, rather than as an instance used
+   * in the configuration. The most common use is if the directive needs space in a @c Context -
+   * that space must be reserved during the invocation of this functor.
+   */
   using CfgInitializer = std::function<swoc::Errata (Config& cfg)>;
 
   /** Information about a directive type.
@@ -81,6 +88,13 @@ class Directive {
    */
   virtual swoc::Errata invoke(Context &ctx) = 0;
 
+  /** Configuration initializer.
+   *
+   * @param Config& Configuration object.
+   * @return Errors, if any.
+   *
+   * Default implementation that does nothing. Override as needed.
+   */
   static swoc::Errata cfg_init(Config&) { return {}; }
 
 protected:
diff --git a/plugin/include/txn_box/common.h b/plugin/include/txn_box/common.h
index 8412700..d5a72f2 100644
--- a/plugin/include/txn_box/common.h
+++ b/plugin/include/txn_box/common.h
@@ -20,6 +20,8 @@
 #include <swoc/Lexicon.h>
 #include <swoc/bwf_fwd.h>
 
+constexpr swoc::TextView DEBUG_TAG = "txn_box";
+
 // Forward declares
 class Config;
 class Context;
@@ -31,6 +33,10 @@ template < typename ... Args > swoc::Errata Error(std::string_view const& fmt, A
   return std::move(swoc::Errata().note_v(swoc::Severity::ERROR, fmt, std::forward_as_tuple(args...)));
 }
 
+template < typename ... Args > swoc::Errata Warning(std::string_view const& fmt, Args && ... args) {
+  return std::move(swoc::Errata().note_v(swoc::Severity::WARN, fmt, std::forward_as_tuple(args...)));
+}
+
 /// Separate a name and argument for a directive or extractor.
 extern swoc::Rv<swoc::TextView> parse_arg(swoc::TextView & key);
 
diff --git a/plugin/include/txn_box/ts_util.h b/plugin/include/txn_box/ts_util.h
index bc22949..1d29321 100644
--- a/plugin/include/txn_box/ts_util.h
+++ b/plugin/include/txn_box/ts_util.h
@@ -28,6 +28,22 @@ extern std::array<TSHttpHookID, std::tuple_size<Hook>::value> TS_Hook;
 
 namespace ts {
 
+template < typename ... Args >
+void DebugMsg(swoc::TextView fmt, Args && ... args) {
+  swoc::LocalBufferWriter<1024> w;
+  auto arg_pack = std::forward_as_tuple(args...);
+  w.print_v(fmt, arg_pack);
+  if (! w.error()) {
+    TSDebug("txn_box", "%.*s", w.size(), w.data());
+  }
+  // Do it the hard way.
+  std::vector<char> buff;
+  buff.resize(w.extent());
+  swoc::FixedBufferWriter fw(buff.data(), buff.size());
+  fw.print_v(fmt, arg_pack);
+  TSDebug("txn_box", "%.*s", fw.size(), fw.data());
+}
+
 /** Hold a string allocated from TS core.
  * This provides both a view of the string and clean up when destructed.
  */
@@ -120,14 +136,9 @@ class URL : public HeapObject {
    */
   self_type & host_set(swoc::TextView const& host);
 
-  in_port_t port_get() {
-    return TSUrlPortGet(_buff, _loc);
-  }
+  in_port_t port_get();
 
-  self_type & port_set(in_port_t port) {
-    TSUrlPortSet(_buff, _loc, port);
-    return *this;
-  }
+  self_type & port_set(in_port_t port);
 
   self_type & path_set(swoc::TextView path) {
     TSUrlPathSet(_buff, _loc, path.data(), path.size());
@@ -265,8 +276,9 @@ class HttpRequest : public HttpHeader {
    */
   URL url();
 
-  swoc::TextView method() const { int length; auto text = TSHttpHdrMethodGet(_buff, _loc, &length); return { text, static_cast<size_t>(length) }; }
+  swoc::TextView method() const;
   swoc::TextView host() const;
+  in_port_t port() const;
 
   /** Set the @a host for the request.
    *
@@ -275,10 +287,19 @@ class HttpRequest : public HttpHeader {
    *
    * This will update the request as little as possible. If the URL does not contain a host
    * then it is unmodified and the @c Host field is set to @a host. If the URL has a host and
-   * there is no @c Host field, only the URL is updated.
+   * there is no @c Host field, only the URL is updated. The port is not updated.
    */
   bool host_set(swoc::TextView const& host);
 
+  /** Set the port.
+   *
+   * @param port Port in host order.
+   * @return If the port was updated.
+   *
+   * This updates the URL and @c Host field as needed, making as few changes as possible.
+   */
+  bool port_set(in_port_t port);
+
   bool scheme_set(swoc::TextView const& scheme);
 };
 
@@ -449,6 +470,8 @@ inline bool HeapObject::is_valid() const { return _buff != nullptr && _loc != nu
 
 inline URL::URL(TSMBuffer buff, TSMLoc loc) : super_type(buff, loc) {}
 
+inline in_port_t URL::port_get() { return TSUrlPortGet(_buff, _loc); }
+
 inline swoc::TextView URL::scheme() const { int length; auto text = TSUrlSchemeGet(_buff, _loc, &length); return { text, static_cast<size_t>(length) }; }
 
 inline swoc::TextView URL::path() const { int length; auto text = TSUrlPathGet(_buff, _loc, &length); return { text, static_cast<size_t>(length) }; }
@@ -462,6 +485,11 @@ inline URL &URL::host_set(swoc::TextView const& host) {
   return *this;
 }
 
+inline auto URL::port_set(in_port_t port) -> self_type & {
+  TSUrlPortSet(_buff, _loc, port);
+  return *this;
+}
+
 inline URL &URL::scheme_set(swoc::TextView const& scheme) {
   if (this->is_valid()) {
     TSUrlSchemeSet(_buff, _loc, scheme.data(), scheme.size());
diff --git a/plugin/src/Features.cc b/plugin/src/Features.cc
index 34641c2..adb5b9e 100644
--- a/plugin/src/Features.cc
+++ b/plugin/src/Features.cc
@@ -323,14 +323,7 @@ Feature Ex_ua_req_host::extract(Context &ctx, Spec const&) {
   FeatureView zret;
   zret._direct_p = true;
   if ( auto hdr { ctx.creq_hdr() } ; hdr.is_valid()) {
-    if ( ts::URL url { hdr.url() } ; url.is_valid()) {
-      zret = url.host();
-      if (zret.data() == nullptr) { // not in the URL, look in the HOST field.
-        if ( auto field { hdr.field(ts::HTTP_FIELD_HOST) } ; field.is_valid()) {
-          zret = field.value();
-        }
-      }
-    }
+    zret = hdr.host();
   }
   return zret;
 }
@@ -451,6 +444,20 @@ ts::HttpHeader Ex_ua_req_field::hdr(Context & ctx) const {
   return ctx.creq_hdr();
 }
 // -----
+class Ex_proxy_req_field : public ExHttpField {
+public:
+  static constexpr TextView NAME { "proxy-req-field" };
+
+protected:
+  TextView const& key() const override;
+  ts::HttpHeader hdr(Context & ctx) const override;
+};
+
+TextView const& Ex_proxy_req_field::key() const { return NAME; }
+ts::HttpHeader Ex_proxy_req_field::hdr(Context & ctx) const {
+  return ctx.preq_hdr();
+}
+// -----
 class Ex_proxy_rsp_field : public ExHttpField {
 public:
   static constexpr TextView NAME { "proxy-rsp-field" };
@@ -898,6 +905,7 @@ Ex_proxy_req_host proxy_req_host;
 Ex_proxy_req_path proxy_req_path;
 Ex_proxy_req_url proxy_req_url;
 Ex_proxy_req_scheme proxy_req_scheme;
+Ex_proxy_req_field proxy_req_field;
 
 Ex_proxy_rsp_status proxy_rsp_status;
 Ex_proxy_rsp_field proxy_rsp_field;
@@ -946,6 +954,7 @@ Ex_remainder_feature ex_remainder_feature;
   Extractor::define(Ex_proxy_req_url::NAME, &proxy_req_url);
   Extractor::define(Ex_proxy_req_path::NAME, &proxy_req_path);
   Extractor::define(Ex_proxy_req_scheme::NAME, &proxy_req_scheme);
+  Extractor::define(Ex_proxy_req_field::NAME, &proxy_req_field);
 
   Extractor::define(Ex_proxy_rsp_status::NAME, &proxy_rsp_status);
   Extractor::define(Ex_proxy_rsp_field::NAME, &proxy_rsp_field);
diff --git a/plugin/src/Machinery.cc b/plugin/src/Machinery.cc
index d78ab1a..360e4f0 100644
--- a/plugin/src/Machinery.cc
+++ b/plugin/src/Machinery.cc
@@ -34,6 +34,57 @@ using namespace swoc::literals;
 /* ------------------------------------------------------------------------------------ */
 Feature Generic::extract() const { return NIL_FEATURE; }
 /* ------------------------------------------------------------------------------------ */
+class Do_ua_req_url_host : public Directive {
+  using super_type = Directive;
+  using self_type = Do_ua_req_url_host;
+public:
+  static const std::string KEY;
+  static const HookMask HOOKS; ///< Valid hooks for directive.
+
+  /** Construct with feature expression..
+   *
+   * @param expr Feature expression.
+   */
+  Do_ua_req_url_host(Expr && expr);
+
+  Errata invoke(Context &ctx) override;
+  static Rv<Handle> load( Config& cfg, YAML::Node drtv_node, swoc::TextView const& name
+                          , swoc::TextView const& arg, YAML::Node key_value);
+protected:
+  Expr _expr; ///< Feature expression.
+};
+
+const std::string Do_ua_req_url_host::KEY {"ua-req-url-host" };
+const HookMask Do_ua_req_url_host::HOOKS {MaskFor({Hook::PREQ, Hook::PRE_REMAP, Hook::POST_REMAP}) };
+
+Do_ua_req_url_host::Do_ua_req_url_host(Expr && expr) : _expr(std::move(expr)) {}
+
+Errata Do_ua_req_url_host::invoke(Context &ctx) {
+  if (auto hdr{ctx.creq_hdr()}; hdr.is_valid()) {
+    if (auto url{hdr.url()}; url.is_valid()) {
+      auto value = ctx.extract(_expr);
+      if (auto host = std::get_if<IndexFor(STRING)>(&value); nullptr != host) {
+        url.host_set(*host);
+      }
+    }
+  }
+  return {};
+}
+
+swoc::Rv<Directive::Handle> Do_ua_req_url_host::load(Config& cfg, YAML::Node drtv_node, swoc::TextView const& name, swoc::TextView const& arg, YAML::Node key_value) {
+  auto && [ expr, errata ] { cfg.parse_expr(key_value) };
+  if (! errata.is_ok()) {
+    errata.info(R"(While parsing "{}" directive at {}.)", KEY, drtv_node.Mark());
+    return std::move(errata);
+  }
+  if (! expr.result_type().can_satisfy(STRING)) {
+    return Error(R"(Value for "{}" directive at {} must be a {}.)", KEY, drtv_node.Mark(), STRING);
+  }
+  return Handle(new self_type{std::move(expr)});
+}
+
+// ---
+
 class Do_proxy_req_url_host : public Directive {
   using super_type = Directive;
   using self_type = Do_proxy_req_url_host;
@@ -41,26 +92,95 @@ class Do_proxy_req_url_host : public Directive {
   static const std::string KEY;
   static const HookMask HOOKS; ///< Valid hooks for directive.
 
-  explicit Do_proxy_req_url_host(TextView text) : _host(text) {}
+  /** Construct with feature expression..
+   *
+   * @param expr Feature expression.
+   */
+  Do_proxy_req_url_host(Expr && expr);
 
   Errata invoke(Context &ctx) override;
   static Rv<Handle> load( Config& cfg, YAML::Node drtv_node, swoc::TextView const& name
                           , swoc::TextView const& arg, YAML::Node key_value);
-  std::string _host;
+protected:
+  Expr _expr; ///< Host feature expression.
 };
 
 const std::string Do_proxy_req_url_host::KEY {"proxy-req-url-host" };
 const HookMask Do_proxy_req_url_host::HOOKS {MaskFor({Hook::PREQ, Hook::PRE_REMAP, Hook::POST_REMAP}) };
 
+Do_proxy_req_url_host::Do_proxy_req_url_host(Expr && expr) : _expr(std::move(expr)) {}
+
 Errata Do_proxy_req_url_host::invoke(Context &ctx) {
-  Errata zret;
-  return zret;
+  if (auto hdr{ctx.preq_hdr()}; hdr.is_valid()) {
+    if (auto url{hdr.url()}; url.is_valid()) {
+      auto value = ctx.extract(_expr);
+      if (auto host = std::get_if<IndexFor(STRING)>(&value); nullptr != host) {
+        url.host_set(*host);
+      }
+    }
+  }
+  return {};
 }
 
 swoc::Rv<Directive::Handle> Do_proxy_req_url_host::load(Config& cfg, YAML::Node drtv_node, swoc::TextView const& name, swoc::TextView const& arg, YAML::Node key_value) {
-  return { Handle{new self_type{key_value.Scalar()}}, {} };
+  auto && [ expr, errata ] { cfg.parse_expr(key_value) };
+  if (! errata.is_ok()) {
+    errata.info(R"(While parsing "{}" directive at {}.)", KEY, drtv_node.Mark());
+    return std::move(errata);
+  }
+  if (! expr.result_type().can_satisfy(STRING)) {
+    return Error(R"(Value for "{}" directive at {} must be a {}.)", KEY, drtv_node.Mark(), STRING);
+  }
+  return Handle(new self_type{std::move(expr)});
 }
 
+// ---
+
+class Do_remap_req_url_host : public Directive {
+  using super_type = Directive;
+  using self_type = Do_remap_req_url_host;
+public:
+  static const std::string KEY;
+  static const HookMask HOOKS; ///< Valid hooks for directive.
+
+  /** Construct with feature expression..
+   *
+   * @param expr Feature expression.
+   */
+  Do_remap_req_url_host(Expr && expr);
+
+  Errata invoke(Context &ctx) override;
+  static Rv<Handle> load( Config& cfg, YAML::Node drtv_node, swoc::TextView const& name
+                          , swoc::TextView const& arg, YAML::Node key_value);
+protected:
+  Expr _expr; ///< Host feature expression.
+};
+
+const std::string Do_remap_req_url_host::KEY {"remap-url-host" };
+const HookMask Do_remap_req_url_host::HOOKS {MaskFor({Hook::PREQ, Hook::PRE_REMAP, Hook::POST_REMAP}) };
+
+Do_remap_req_url_host::Do_remap_req_url_host(Expr && expr) : _expr(std::move(expr)) {}
+
+Errata Do_remap_req_url_host::invoke(Context &ctx) {
+  auto value = ctx.extract(_expr);
+  if (auto host = std::get_if<IndexFor(STRING)>(&value); nullptr != host) {
+    ts::URL(ctx._remap_info->requestBufp, ctx._remap_info->requestUrl).host_set(*host);
+    ctx._remap_status = TSREMAP_DID_REMAP;
+  }
+  return {};
+}
+
+swoc::Rv<Directive::Handle> Do_remap_req_url_host::load(Config& cfg, YAML::Node drtv_node, swoc::TextView const& name, swoc::TextView const& arg, YAML::Node key_value) {
+  auto && [ expr, errata ] { cfg.parse_expr(key_value) };
+  if (! errata.is_ok()) {
+    errata.info(R"(While parsing "{}" directive at {}.)", KEY, drtv_node.Mark());
+    return std::move(errata);
+  }
+  if (! expr.result_type().can_satisfy(STRING)) {
+    return Error(R"(Value for "{}" directive at {} must be a {}.)", KEY, drtv_node.Mark(), STRING);
+  }
+  return Handle(new self_type{std::move(expr)});
+}
 /* ------------------------------------------------------------------------------------ */
 /** Set the host for the request.
  * This updates both the URL and the "Host" field, if appropriate.
@@ -72,11 +192,11 @@ class Do_ua_req_host : public Directive {
   static const std::string KEY; ///< Directive name.
   static const HookMask HOOKS; ///< Valid hooks for directive.
 
-  /** Construct with feature extractor @a fmt.
+  /** Construct with feature expression..
    *
-   * @param fmt Feature for host.
+   * @param expr Feature expression.
    */
-  Do_ua_req_host(Expr && fmt);
+  Do_ua_req_host(Expr && expr);
 
   /** Invoke directive.
    *
@@ -98,18 +218,20 @@ class Do_ua_req_host : public Directive {
                           , swoc::TextView const& arg, YAML::Node key_value);
 
 protected:
-  Expr _fmt; ///< Host feature.
+  Expr _expr; ///< Host feature.
 };
 
 const std::string Do_ua_req_host::KEY {"ua-req-host" };
 const HookMask Do_ua_req_host::HOOKS {MaskFor({Hook::CREQ, Hook::PRE_REMAP, Hook::POST_REMAP}) };
 
-Do_ua_req_host::Do_ua_req_host(Expr &&fmt) : _fmt(std::move(fmt)) {}
+Do_ua_req_host::Do_ua_req_host(Expr &&expr) : _expr(std::move(expr)) {}
 
 Errata Do_ua_req_host::invoke(Context &ctx) {
-  TextView host{std::get<IndexFor(STRING)>(ctx.extract(_fmt))};
   if (auto hdr{ctx.creq_hdr()}; hdr.is_valid()) {
-    hdr.host_set(host);
+    auto value = ctx.extract(_expr);
+    if (auto host = std::get_if<IndexFor(STRING)>(&value); nullptr != host) {
+      hdr.host_set(*host);
+    }
   }
   return {};
 }
diff --git a/plugin/src/ip_space.cc b/plugin/src/ip_space.cc
index 2f5faa3..72588e4 100644
--- a/plugin/src/ip_space.cc
+++ b/plugin/src/ip_space.cc
@@ -243,12 +243,15 @@ class Do_ip_space_define : public Directive {
 
   int _line_no = 0; ///< For debugging name conflicts.
 
+  /// YAML key names.
+  ///@{
   static const std::string NAME_TAG;
   static const std::string PATH_TAG;
   static const std::string COLUMNS_TAG;
   static const std::string DURATION_TAG;
   static const std::string TYPE_TAG;
   static const std::string VALUES_TAG;
+  ///@}
 
   SpaceHandle acquire_space() {
     std::shared_lock lock(_space_mutex);
diff --git a/plugin/src/ts_util.cc b/plugin/src/ts_util.cc
index 62a6981..876b826 100644
--- a/plugin/src/ts_util.cc
+++ b/plugin/src/ts_util.cc
@@ -8,7 +8,7 @@
 #include <string>
 #include <map>
 #include <numeric>
-#include <getopt.h>
+#include <alloca.h>
 
 #include <openssl/ssl.h>
 
@@ -16,16 +16,8 @@
 #include <swoc/swoc_file.h>
 #include <swoc/bwf_std.h>
 #include <swoc/swoc_meta.h>
-#include <yaml-cpp/yaml.h>
-
-#include "txn_box/Directive.h"
-#include "txn_box/Extractor.h"
-#include "txn_box/Modifier.h"
-#include "txn_box/Config.h"
-#include "txn_box/Context.h"
 
 #include "txn_box/ts_util.h"
-#include "txn_box/yaml_util.h"
 
 using swoc::TextView;
 using swoc::Errata;
@@ -224,23 +216,90 @@ ts::URL ts::HttpRequest::url() {
   return {};
 }
 
+TextView ts::HttpRequest::host() const {
+  auto url { const_cast<self_type*>(this)->url() };
+  if (auto host = url.host() ; ! host.empty()) {
+    return host;
+  }
+  if (auto field = this->field(HTTP_FIELD_HOST) ; field.is_valid()) {
+    auto value = field.value();
+    TextView host_token, port_token, rest_token;
+    if (swoc::IPEndpoint::tokenize(value, &host_token, &port_token)) {
+      return host_token;
+    }
+  }
+  return {};
+}
+
+in_port_t ts::HttpRequest::port() const {
+  auto url { const_cast<self_type*>(this)->url() };
+  if (auto port = url.port_get() ; port != 0) {
+    return port;
+  }
+  if (auto field = this->field(HTTP_FIELD_HOST) ; field.is_valid()) {
+    auto value = field.value();
+    TextView host_token, port_token, rest_token;
+    if (swoc::IPEndpoint::tokenize(value, &host_token, &port_token)) {
+      return swoc::svtoi(port_token);
+    }
+  }
+  return 0;
+}
+
 bool ts::HttpRequest::host_set(swoc::TextView const &host) {
   auto url{this->url()};
+  bool force_host_p = true;
   if (!url.host().empty()) {
     url.host_set(host);
-    if (auto field{this->field(HTTP_FIELD_HOST)}; field.is_valid()) {
+    force_host_p = false;
+  }
+  auto field{this->field(HTTP_FIELD_HOST)};
+  if (field.is_valid()) {
+    auto text = field.value();
+    TextView host_token, port_token, rest_token;
+    if (swoc::IPEndpoint::tokenize(text, &host_token, &port_token)) {
+      size_t n = host.size() + 1 + port_token.size();
+      swoc::FixedBufferWriter w{static_cast<char*>(alloca(n)), n};
+      w.print("{}:{}", host, port_token);
+      field.assign(w.view());
+    } else { // It's messed up, do the best we can by setting it to a valid value.
       field.assign(host);
     }
-  } else {
-    this->field_obtain(HTTP_FIELD_HOST).assign(host);
+  } else if (force_host_p) {
+    this->field_create(HTTP_FIELD_HOST).assign(host);
   }
   return true;
-};
+}
+
+bool ts::HttpRequest::port_set(in_port_t port) {
+  auto url{this->url()};
+  if (!url.host().empty()) {
+    url.port_set(port);
+  }
+  auto field{this->field(HTTP_FIELD_HOST)};
+  if (field.is_valid()) {
+    auto text = field.value();
+    TextView host_token, port_token, rest_token;
+    if (swoc::IPEndpoint::tokenize(text, &host_token, &port_token)) {
+      size_t n = host_token.size() + 1 + std::numeric_limits<in_port_t>::max_digits10;
+      swoc::FixedBufferWriter w{static_cast<char*>(alloca(n)), n};
+      w.print("{}:{}", host_token, port);
+      field.assign(w.view());
+    }
+  }
+  return true;
+}
 
 bool ts::HttpRequest::scheme_set(swoc::TextView const &scheme) {
   this->url().scheme_set(scheme);
   return true;
-};
+}
+
+swoc::TextView HttpRequest::method() const { int length;
+  char const *text;
+  text = TSHttpHdrMethodGet(_buff, _loc, &length);
+  return {text, static_cast<size_t>(length) };
+}
 
 ts::HttpRequest ts::HttpTxn::creq_hdr() {
   TSMBuffer buff;
diff --git a/plugin/src/txn_box.cc b/plugin/src/txn_box.cc
index 2b1dffa..a508dd1 100644
--- a/plugin/src/txn_box.cc
+++ b/plugin/src/txn_box.cc
@@ -8,6 +8,8 @@
 #include <string>
 #include <map>
 #include <numeric>
+
+#include <glob.h>
 #include <getopt.h>
 
 #include <openssl/ssl.h>
@@ -35,12 +37,13 @@ using namespace swoc::literals;
 /* ------------------------------------------------------------------------------------ */
 
 Global G;
+extern std::string glob_to_rxp(TextView glob);
 
 const std::string Config::ROOT_KEY { "txn_box" };
 
 Hook Convert_TS_Event_To_TxB_Hook(TSEvent ev) {
   static const std::map<TSEvent, Hook> table{
-        {TS_EVENT_HTTP_READ_REQUEST_HDR,  Hook::CREQ}
+      {TS_EVENT_HTTP_READ_REQUEST_HDR,  Hook::CREQ}
       , {TS_EVENT_HTTP_SEND_REQUEST_HDR,  Hook::PREQ}
       , {TS_EVENT_HTTP_READ_RESPONSE_HDR, Hook::URSP}
       , {TS_EVENT_HTTP_SEND_RESPONSE_HDR, Hook::PRSP}
@@ -54,9 +57,55 @@ Hook Convert_TS_Event_To_TxB_Hook(TSEvent ev) {
 }
 
 namespace {
+
  std::shared_ptr<Config> Plugin_Config;
+
 } // namespace
 /* ------------------------------------------------------------------------------------ */
+Errata Config::load_file(swoc::file::path const& cfg_path, TextView cfg_key) {
+  if (auto spot = _cfg_files.find(cfg_path.view()) ; spot != _cfg_files.end() ) {
+    ts::DebugMsg("Skipping {} - already loaded", cfg_path);
+    return {};
+  }
+  auto fi = _arena.make<FileInfo>(this->localize(cfg_path.view()));
+  _cfg_files.insert(fi);
+  // Try loading and parsing the file.
+  auto &&[root, yaml_errata ]{yaml_load(cfg_path)};
+  if (!yaml_errata.is_ok()) {
+    yaml_errata.info(R"(While loading file "{}".)", cfg_path);
+    return std::move(yaml_errata);
+  }
+
+  // Process the YAML data.
+  auto errata = Plugin_Config->parse_yaml(root, cfg_key);
+  if (!errata.is_ok()) {
+    errata.info(R"(While parsing key "{}" in configuration file "{}".)", cfg_key, cfg_path);
+    return std::move(errata);
+  }
+
+  return {};
+}
+/* ------------------------------------------------------------------------------------ */
+Errata Config::load_file_glob(TextView pattern, swoc::TextView cfg_key) {
+  int flags = 0;
+  glob_t files;
+  auto err_f = [](char const* path, int err) -> int { return 0; };
+  swoc::file::path abs_pattern = ts::make_absolute(pattern);
+  int result = glob(abs_pattern.c_str(), flags, err_f, &files);
+  if (result == GLOB_NOMATCH) {
+    return Warning(R"(The pattern "{}" did not match any files.)", abs_pattern);
+  }
+  for ( size_t idx = 0 ; idx < files.gl_pathc ; ++idx) {
+    auto errata = this->load_file(swoc::file::path(files.gl_pathv[idx]), cfg_key);
+    if (! errata.is_ok()) {
+      errata.info(R"(While processing pattern "{}".)", pattern);
+      return std::move(errata);
+    }
+  }
+  globfree(&files);
+  return {};
+}
+/* ------------------------------------------------------------------------------------ */
 void Global::reserve_txn_arg() {
   if (G.TxnArgIdx < 0) {
     auto && [ idx, errata ] { ts::HttpTxn::reserve_arg(Config::ROOT_KEY, "Transaction Box") };
@@ -92,7 +141,7 @@ TxnBoxInit(int argc, char const *argv[]) {
                                 , "solidwallofcode@verizonmedia.com"};
 
   Plugin_Config.reset(new Config);
-  TextView cfg_path { "txn_box.yaml" };
+//  swoc::file::path cfg_path { "txn_box.yaml" };
   TextView cfg_key { Config::ROOT_KEY };
   int opt;
   int idx;
@@ -101,7 +150,11 @@ TxnBoxInit(int argc, char const *argv[]) {
     switch (opt) {
       case ':':errata.error("'{}' requires a value", argv[optind - 1]);
         break;
-      case 'c': cfg_path.assign(argv[optind-1], strlen(argv[optind-1]));
+      case 'c':
+        errata = Plugin_Config->load_file_glob({argv[optind-1], strlen(argv[optind-1])}, cfg_key);
+        if (!errata.is_ok()) {
+          return std::move(errata);
+        }
         break;
       case 'k': cfg_key.assign(argv[optind-1], strlen(argv[optind-1]));
         break;
@@ -110,24 +163,6 @@ TxnBoxInit(int argc, char const *argv[]) {
     }
   }
 
-  if (!errata.is_ok()) {
-    return std::move(errata);
-  }
-
-  // Try loading and parsing the file.
-  auto &&[root, yaml_errata ]{yaml_load(cfg_path)};
-  if (!yaml_errata.is_ok()) {
-    yaml_errata.info(R"(While loading file "{}".)", cfg_path);
-    return std::move(yaml_errata);
-  }
-
-  // Process the YAML data.
-  errata = Plugin_Config->parse_yaml(root, cfg_key);
-  if (!errata.is_ok()) {
-    errata.info(R"(While parsing key "{}" in configuration file "{}".)", cfg_key, cfg_path);
-    return std::move(errata);
-  }
-
   if (TSPluginRegister(&info) == TS_SUCCESS) {
     auto& post_load_directives = Plugin_Config->hook_directives(Hook::POST_LOAD);
     if (post_load_directives.size() > 0) {
diff --git a/test/autest/gold_tests/autest-site/txn_box.test.ext b/test/autest/gold_tests/autest-site/txn_box.test.ext
index e57b1b0..28c2eee 100755
--- a/test/autest/gold_tests/autest-site/txn_box.test.ext
+++ b/test/autest/gold_tests/autest-site/txn_box.test.ext
@@ -51,3 +51,63 @@ def ConfigureTsForTxnBox(run, ts, server, txn_box_config=None, txn_box_key='meta
 
 ##########################################################################
 ExtendTestRun(ConfigureTsForTxnBox, name="ConfigureTsForTxnBox")
+
+
+def TxnBoxTestRun(self, text, replay_path, **kw):
+  """
+  Set up a standard test run for TxnBox
+
+  Args:
+    text: Description for test run.
+    replay_path: Path to the replay file.
+  Keywords
+    replay: The replay file.
+  """
+
+  config_key = kw.get("config_key")
+  config_path = kw.get("config_path", replay_path)
+  run = self.AddTestRun(text)
+
+  ts = self.MakeATSProcess("ts")
+  run.Variables.TS = ts;
+  pv_client = run.AddVerifierClientProcess(
+    "pv-client", ts, replay_path,
+    http_ports=[ts.Variables.port])
+
+  pv_server = run.AddVerifierServerProcess("pv-server", replay_path)
+
+  # Put the txn_box.so into the sandbox.
+  plugin_dir = ts.Env['PROXY_CONFIG_PLUGIN_PLUGIN_DIR']
+  from os.path import dirname
+  git_root = dirname(dirname(dirname(ts.TestRoot)))
+  txn_box_lib = os.path.join(git_root, "lib", "txn_box.so")
+  ts.Setup.Copy(txn_box_lib, plugin_dir, CopyLogic.SoftFiles)
+
+  # Configure txn_box in Traffic Server.
+  txn_box_command = 'txn_box.so '
+
+  if config_key:
+    txn_box_command += ' --key {}'.format(config_key)
+
+  if config_path:
+    ts.Setup.Copy(config_path, ts.Variables.CONFIGDIR)
+    txn_box_command += ' --config {}'.format(os.path.basename(config_path))
+
+  ts.Disk.plugin_config.AddLine(txn_box_command)
+
+  # Configure Traffic Server to use the DNS process.
+  dns = self.MakeDNServer("dns", ip='127.0.0.1', default=['127.0.0.1'])
+
+  ts.Disk.records_config.update({
+    'proxy.config.dns.nameservers': '127.0.0.1:{0}'.format(dns.Variables.Port),
+    'proxy.config.dns.resolv_conf': 'NULL',
+#    'proxy.config.plugin.dynamic_reload': 0
+  })
+
+  run.Processes.Default.StartBefore(pv_server)
+  run.Processes.Default.StartBefore(ts, ready=When.PortOpen(ts.Variables.port))
+  run.Processes.Default.StartBefore(dns)
+
+  return run
+
+ExtendTest(TxnBoxTestRun, name="TxnBoxTestRun")
diff --git a/test/autest/gold_tests/ct_header/ct_header.test.py b/test/autest/gold_tests/ct_header/ct_header.test.py
index 2da2cf7..a6fe9b4 100644
--- a/test/autest/gold_tests/ct_header/ct_header.test.py
+++ b/test/autest/gold_tests/ct_header/ct_header.test.py
@@ -10,15 +10,4 @@
 Test.Summary = '''
 Verify txn_box can filter fields as expected.
 '''
-
-ts = Test.MakeATSProcess("ts")
-
-#
-# Test 1: Verify that a field can be changed in both upstream and downstream
-#
-r = Test.AddTestRun("Verify txn_box can filter fields as expected.")
-client = r.AddVerifierClientProcess(
-    "client1", ts, "ct_header.replay.yaml",
-    http_ports=[ts.Variables.port])
-server = r.AddVerifierServerProcess("server1", "ct_header.replay.yaml")
-r.ConfigureTsForTxnBox(ts, server, "ct_header.replay.yaml")
+r = Test.TxnBoxTestRun("Test HTTP field manipuation", "ct_header.replay.yaml", config_key="meta.txn_box")
diff --git a/test/autest/gold_tests/static_file/static_file.replay.yaml b/test/autest/gold_tests/static_file/static_file.replay.yaml
index 1f3d011..feab7d6 100644
--- a/test/autest/gold_tests/static_file/static_file.replay.yaml
+++ b/test/autest/gold_tests/static_file/static_file.replay.yaml
@@ -22,6 +22,16 @@ meta:
         - upstream-rsp-status: [ 200 , "OK" ]
         - proxy-rsp-body: "Contents of security.txt"
 
+  - when: proxy-req
+    do:
+    - with: proxy-req-path
+      select:
+      - match: "concert.txt"
+        do:
+        - proxy-req-field<Author-i-tay>:
+          - proxy-req-field<Author-i-tay>
+          - else: text-block<SWOC>
+
   txn-box-remap:
   - when: proxy-rsp
     do:
@@ -125,3 +135,60 @@ sessions:
     proxy-response:
       status: 200
 
+  - all: { headers: { fields: [[ uuid, 4 ]]}}
+    client-request:
+      version: "1.1"
+      scheme: "http"
+      method: "GET"
+      url: "/concert.txt"
+      headers:
+        fields:
+        - [ Host, example.one ]
+    proxy-request:
+      version: "1.1"
+      scheme: "http"
+      method: "GET"
+      url: "/concert.txt"
+      headers:
+        fields:
+        - [ Author-i-tay, "Delain Concert.", equal ]
+    server-response:
+      status: 200
+      content:
+        size: 140
+      headers:
+        fields:
+        - [ Content-Type, text/html ]
+        - [ Content-Length, 140 ]
+    proxy-response:
+      status: 200
+
+  - all: { headers: { fields: [[ uuid, 5 ]]}}
+    client-request:
+      version: "1.1"
+      scheme: "http"
+      method: "GET"
+      url: "/concert.txt"
+      headers:
+        fields:
+        - [ Host, example.one ]
+        - [ Author-i-tay, "Nightwish Concert." ]
+    proxy-request:
+      version: "1.1"
+      scheme: "http"
+      method: "GET"
+      url: "/concert.txt"
+      headers:
+        fields:
+        - [ Author-i-tay, "Nightwish Concert.", equal ]
+    server-response:
+      status: 200
+      content:
+        size: 50
+      headers:
+        fields:
+        - [ Content-Type, text/html ]
+        - [ Content-Length, 50 ]
+    proxy-response:
+      status: 200
+
diff --git a/test/autest/gold_tests/static_file/static_file.test.py b/test/autest/gold_tests/static_file/static_file.test.py
index e2a9a62..c8d6068 100644
--- a/test/autest/gold_tests/static_file/static_file.test.py
+++ b/test/autest/gold_tests/static_file/static_file.test.py
@@ -7,27 +7,12 @@
 # SPDX-License-Identifier: Apache-2.0
 #
 
-import os
-
 Test.Summary = '''
 Server static file as response body.
 '''
-
-ts = Test.MakeATSProcess("ts")
-
-#
-# Test 1: Verify that a field can be changed in both upstream and downstream
-#
-r = Test.AddTestRun("Serve static file content.")
-client = r.AddVerifierClientProcess(
-    "client1", ts, "static_file.replay.yaml",
-    http_ports=[ts.Variables.port])
-server = r.AddVerifierServerProcess("server1", "static_file.replay.yaml")
-r.ConfigureTsForTxnBox(ts, server, "static_file.replay.yaml")
+r = Test.TxnBoxTestRun("Test static file support", "static_file.replay.yaml", config_key="meta.txn_box")
+ts = r.Variables.TS
 ts.Setup.Copy("static_file.txt", ts.Variables.CONFIGDIR)
 ts.Disk.remap_config.AddLine(
-    'map http://example.one http://example.one @plugin=txn_box.so @pparam=../../static_file.replay.yaml @pparam=meta.txn-box-remap'
+    'map http://example.one http://example.one @plugin=txn_box.so @pparam=static_file.replay.yaml @pparam=meta.txn-box-remap'
 )
-ts.Disk.records_config.update({
-    'proxy.config.plugin.dynamic_reload_mode': 0,
-})