diff -up vsftpd-2.2.2/logging.h.dyn_host vsftpd-2.2.2/logging.h
--- vsftpd-2.2.2/logging.h.dyn_host	2010-11-15 10:37:44.767026001 -0700
+++ vsftpd-2.2.2/logging.h	2010-11-19 22:06:32.516919272 -0700
@@ -20,6 +20,7 @@ enum EVSFLogEntryType
   kVSFLogEntryRmdir,
   kVSFLogEntryChmod,
   kVSFLogEntryDebug,
+  kVSFLogEntryDNSResolve,
 };
 
 /* vsf_log_init()
diff -up vsftpd-2.2.2/logging.c.dyn_host vsftpd-2.2.2/logging.c
--- vsftpd-2.2.2/logging.c.dyn_host	2010-11-15 10:37:44.764025999 -0700
+++ vsftpd-2.2.2/logging.c	2010-11-20 00:10:10.500009753 -0700
@@ -330,6 +330,9 @@ vsf_log_do_log_vsftpd_format(struct vsf_
     case kVSFLogEntryDebug:
       str_append_text(p_str, "DEBUG");
       break;
+    case kVSFLogEntryDNSResolve:
+      str_append_text(p_str, "RESOLVE");
+      break;
     default:
       bug("bad entry_type in vsf_log_do_log");
       break;
diff -up vsftpd-2.2.2/main.c.dyn_host vsftpd-2.2.2/main.c
--- vsftpd-2.2.2/main.c.dyn_host	2009-07-17 22:55:53.000000000 -0700
+++ vsftpd-2.2.2/main.c	2010-11-28 09:13:23.646374366 -0700
@@ -118,16 +118,10 @@ main(int argc, const char* argv[])
     }
     vsf_sysutil_free(p_statbuf);
   }
-  /* Resolve pasv_address if required */
-  if (tunable_pasv_address && tunable_pasv_addr_resolve)
+  /* Get hostname from address field if specified */
+  if (tunable_pasv_address && tunable_pasv_addr_resolve && !tunable_pasv_hostname)
   {
-    struct vsf_sysutil_sockaddr* p_addr = 0;
-    const char* p_numeric_addr;
-    vsf_sysutil_dns_resolve(&p_addr, tunable_pasv_address);
-    vsf_sysutil_free((char*) tunable_pasv_address);
-    p_numeric_addr = vsf_sysutil_inet_ntop(p_addr);
-    tunable_pasv_address = vsf_sysutil_strdup(p_numeric_addr);
-    vsf_sysutil_free(p_addr);
+    tunable_pasv_hostname = vsf_sysutil_strdup(tunable_pasv_address);
   }
   if (!tunable_run_as_launching_user)
   {
diff -up vsftpd-2.2.2/parseconf.c.dyn_host vsftpd-2.2.2/parseconf.c
--- vsftpd-2.2.2/parseconf.c.dyn_host	2010-11-15 10:37:44.806026001 -0700
+++ vsftpd-2.2.2/parseconf.c	2010-11-16 01:04:22.097017567 -0700
@@ -91,6 +91,7 @@ parseconf_bool_array[] =
   { "mdtm_write", &tunable_mdtm_write },
   { "lock_upload_files", &tunable_lock_upload_files },
   { "pasv_addr_resolve", &tunable_pasv_addr_resolve },
+  { "pasv_addr_dynamic", &tunable_pasv_addr_dynamic },
   { "userlist_log", &tunable_userlist_log },
   { "debug_ssl", &tunable_debug_ssl },
   { "require_cert", &tunable_require_cert },
@@ -161,6 +162,7 @@ parseconf_str_array[] =
   { "local_root", &tunable_local_root },
   { "banner_file", &tunable_banner_file },
   { "pasv_address", &tunable_pasv_address },
+  { "pasv_hostname", &tunable_pasv_hostname },
   { "listen_address", &tunable_listen_address },
   { "user_config_dir", &tunable_user_config_dir },
   { "listen_address6", &tunable_listen_address6 },
diff -up vsftpd-2.2.2/postlogin.c.dyn_host vsftpd-2.2.2/postlogin.c
--- vsftpd-2.2.2/postlogin.c.dyn_host	2009-11-06 21:55:12.000000000 -0700
+++ vsftpd-2.2.2/postlogin.c	2010-12-13 18:10:09.079196225 -0700
@@ -62,7 +62,6 @@ static void handle_logged_in_user(struct
 static void handle_logged_in_pass(struct vsf_session* p_sess);
 
 static int pasv_active(struct vsf_session* p_sess);
-static int port_active(struct vsf_session* p_sess);
 static void pasv_cleanup(struct vsf_session* p_sess);
 static void port_cleanup(struct vsf_session* p_sess);
 static void handle_dir_common(struct vsf_session* p_sess, int full_details,
@@ -484,21 +483,6 @@ handle_cdup(struct vsf_session* p_sess)
 }
 
 static int
-port_active(struct vsf_session* p_sess)
-{
-  int ret = 0;
-  if (p_sess->p_port_sockaddr != 0)
-  {
-    ret = 1;
-    if (pasv_active(p_sess))
-    {
-      bug("port and pasv both active");
-    }
-  }
-  return ret;
-}
-
-static int
 pasv_active(struct vsf_session* p_sess)
 {
   int ret = 0;
@@ -512,7 +496,7 @@ pasv_active(struct vsf_session* p_sess)
   }
   if (ret)
   {
-    if (port_active(p_sess))
+    if (p_sess->p_port_sockaddr != 0)
     {
       bug("pasv and port both active");
     }
@@ -544,7 +528,7 @@ handle_pasv(struct vsf_session* p_sess, 
 {
   unsigned short the_port;
   static struct mystr s_pasv_res_str;
-  static struct vsf_sysutil_sockaddr* s_p_sockaddr;
+  static struct vsf_sysutil_sockaddr* s_p_sockaddr = 0;
   int is_ipv6 = vsf_sysutil_sockaddr_is_ipv6(p_sess->p_local_addr);
   if (is_epsv && !str_isempty(&p_sess->ftp_arg_str))
   {
@@ -581,18 +565,37 @@ handle_pasv(struct vsf_session* p_sess, 
     vsf_cmdio_write_str(p_sess, FTP_EPSVOK, &s_pasv_res_str);
     return;
   }
-  if (tunable_pasv_address != 0)
+  if (s_p_sockaddr == 0)
   {
-    vsf_sysutil_sockaddr_alloc_ipv4(&s_p_sockaddr);
-    /* Report passive address as specified in configuration */
-    if (vsf_sysutil_inet_aton(tunable_pasv_address, s_p_sockaddr) == 0)
+    vsf_sysutil_sockaddr_clear(&s_p_sockaddr);
+    if (tunable_pasv_hostname)
+    {
+      vsf_sysutil_host_resolve(p_sess, &s_p_sockaddr);
+    }
+    else
     {
-      die("invalid pasv_address");
+      if (tunable_pasv_address != 0)
+      {
+        vsf_sysutil_sockaddr_alloc_ipv4(&s_p_sockaddr);
+        /* Report passive address as specified in configuration */
+        if (vsf_sysutil_inet_aton(tunable_pasv_address, s_p_sockaddr) == 0)
+        {
+        /*  log message "invalid pasv_address, using default" */
+          vsf_sysutil_sockaddr_clone(&s_p_sockaddr, p_sess->p_local_addr);
+        }
+      }
+      else
+      {
+        vsf_sysutil_sockaddr_clone(&s_p_sockaddr, p_sess->p_local_addr);
+      }
     }
   }
   else
   {
-    vsf_sysutil_sockaddr_clone(&s_p_sockaddr, p_sess->p_local_addr);
+    if (tunable_pasv_addr_dynamic)
+    {
+      vsf_sysutil_host_resolve(p_sess, &s_p_sockaddr);
+    }
   }
   str_alloc_text(&s_pasv_res_str, "Entering Passive Mode (");
   if (!is_ipv6)
@@ -1378,7 +1381,7 @@ static int
 get_remote_transfer_fd(struct vsf_session* p_sess, const char* p_status_msg)
 {
   int remote_fd;
-  if (!pasv_active(p_sess) && !port_active(p_sess))
+  if (!pasv_active(p_sess) && p_sess->p_port_sockaddr == 0)
   {
     bug("neither PORT nor PASV active in get_remote_transfer_fd");
   }
@@ -1828,7 +1831,7 @@ handle_stat_file(struct vsf_session* p_s
 static int
 data_transfer_checks_ok(struct vsf_session* p_sess)
 {
-  if (!pasv_active(p_sess) && !port_active(p_sess))
+  if (!pasv_active(p_sess) && p_sess->p_port_sockaddr == 0)
   {
     vsf_cmdio_write(p_sess, FTP_BADSENDCONN, "Use PORT or PASV first.");
     return 0;
diff -up vsftpd-2.2.2/sysutil.h.dyn_host vsftpd-2.2.2/sysutil.h
--- vsftpd-2.2.2/sysutil.h.dyn_host	2010-11-15 10:37:45.015026001 -0700
+++ vsftpd-2.2.2/sysutil.h	2010-11-29 08:43:42.901802833 -0700
@@ -261,8 +261,9 @@ int vsf_sysutil_accept_timeout(int fd, s
 int vsf_sysutil_connect_timeout(int fd,
                                 const struct vsf_sysutil_sockaddr* p_sockaddr,
                                 unsigned int wait_seconds);
-void vsf_sysutil_dns_resolve(struct vsf_sysutil_sockaddr** p_sockptr,
-                             const char* p_name);
+struct vsf_session;
+void vsf_sysutil_host_resolve(struct vsf_session* p_sess,
+                              struct vsf_sysutil_sockaddr** p_sockptr);
 /* Option setting on sockets */
 void vsf_sysutil_v6only(int fd);
 void vsf_sysutil_activate_keepalive(int fd);
diff -up vsftpd-2.2.2/sysutil.c.dyn_host vsftpd-2.2.2/sysutil.c
--- vsftpd-2.2.2/sysutil.c.dyn_host	2010-11-15 10:37:45.012025999 -0700
+++ vsftpd-2.2.2/sysutil.c	2010-12-14 10:48:18.796665459 -0700
@@ -16,6 +16,8 @@
 #include "utility.h"
 #include "tunables.h"
 #include "sysdeputil.h"
+#include "logging.h"
+#include "str.h"
 
 /* Activate 64-bit file support on Linux/32bit plus others */
 #define _FILE_OFFSET_BITS 64
@@ -2261,40 +2263,58 @@ vsf_sysutil_inet_aton(const char* p_text
 }
 
 void
-vsf_sysutil_dns_resolve(struct vsf_sysutil_sockaddr** p_sockptr,
-                        const char* p_name)
+vsf_sysutil_host_resolve(struct vsf_session* p_sess,
+                         struct vsf_sysutil_sockaddr** p_sockptr)
 {
-  struct hostent* hent = gethostbyname(p_name);
+  struct hostent* hent = gethostbyname(tunable_pasv_hostname);
   if (hent == NULL)
   {
-    die2("cannot resolve host:", p_name);
-  }
-  vsf_sysutil_sockaddr_clear(p_sockptr);
-  if (hent->h_addrtype == AF_INET)
-  {
-    unsigned int len = hent->h_length;
-    if (len > sizeof((*p_sockptr)->u.u_sockaddr_in.sin_addr))
+    struct mystr str_log_line = INIT_MYSTR;
+    str_alloc_text(&str_log_line, "cannot resolve host:");
+    str_append_text(&str_log_line, tunable_pasv_hostname);
+    str_append_text(&str_log_line, ", using:");
+    if (tunable_pasv_address)
     {
-      len = sizeof((*p_sockptr)->u.u_sockaddr_in.sin_addr);
+      str_append_text(&str_log_line, tunable_pasv_address);
     }
-    vsf_sysutil_sockaddr_alloc_ipv4(p_sockptr);
-    vsf_sysutil_memcpy(&(*p_sockptr)->u.u_sockaddr_in.sin_addr,
-                       hent->h_addr_list[0], len);
-  }
-  else if (hent->h_addrtype == AF_INET6)
-  {
-    unsigned int len = hent->h_length;
-    if (len > sizeof((*p_sockptr)->u.u_sockaddr_in6.sin6_addr))
+    else
     {
-      len = sizeof((*p_sockptr)->u.u_sockaddr_in6.sin6_addr);
+      str_append_text(&str_log_line, "default (incoming socket address)");
     }
-    vsf_sysutil_sockaddr_alloc_ipv6(p_sockptr);
-    vsf_sysutil_memcpy(&(*p_sockptr)->u.u_sockaddr_in6.sin6_addr,
-                       hent->h_addr_list[0], len);
+    vsf_log_failed_line(p_sess, kVSFLogEntryDNSResolve, &str_log_line);
+    str_free(&str_log_line);
   }
   else
   {
-    die("gethostbyname(): neither IPv4 nor IPv6");
+    if (hent->h_addrtype == AF_INET)
+    {
+      unsigned int len = hent->h_length;
+      if (len > sizeof((*p_sockptr)->u.u_sockaddr_in.sin_addr))
+      {
+        len = sizeof((*p_sockptr)->u.u_sockaddr_in.sin_addr);
+      }
+      vsf_sysutil_sockaddr_alloc_ipv4(p_sockptr);
+      vsf_sysutil_memcpy(&(*p_sockptr)->u.u_sockaddr_in.sin_addr,
+                         hent->h_addr_list[0], len);
+    }
+    else if (hent->h_addrtype == AF_INET6)
+    {
+      unsigned int len = hent->h_length;
+      if (len > sizeof((*p_sockptr)->u.u_sockaddr_in6.sin6_addr))
+      {
+        len = sizeof((*p_sockptr)->u.u_sockaddr_in6.sin6_addr);
+      }
+      vsf_sysutil_sockaddr_alloc_ipv6(p_sockptr);
+      vsf_sysutil_memcpy(&(*p_sockptr)->u.u_sockaddr_in6.sin6_addr,
+                         hent->h_addr_list[0], len);
+    }
+    else
+    {
+      struct mystr str_log_line = INIT_MYSTR;
+      str_alloc_text(&str_log_line, "neither IPv4 nor IPv6, using default");
+      vsf_log_failed_line(p_sess, kVSFLogEntryDNSResolve, &str_log_line);
+      str_free(&str_log_line);
+    }
   }
 }
 
diff -up vsftpd-2.2.2/tunables.h.dyn_host vsftpd-2.2.2/tunables.h
--- vsftpd-2.2.2/tunables.h.dyn_host	2010-11-15 10:37:44.774026001 -0700
+++ vsftpd-2.2.2/tunables.h	2010-11-16 00:26:31.450026007 -0700
@@ -73,6 +73,7 @@ extern int tunable_force_anon_data_ssl; 
 extern int tunable_mdtm_write;                /* Allow MDTM to set timestamps */
 extern int tunable_lock_upload_files;         /* Lock uploading files */
 extern int tunable_pasv_addr_resolve;         /* DNS resolve pasv_addr */
+extern int tunable_pasv_addr_dynamic;         /* DNS dynamic pasv_addr */
 extern int tunable_userlist_log;              /* Log every failed login attempt */
 extern int tunable_debug_ssl;                 /* Verbose SSL logging */
 extern int tunable_require_cert;              /* SSL client cert required */
@@ -127,6 +128,7 @@ extern const char* tunable_anon_root;
 extern const char* tunable_local_root;
 extern const char* tunable_banner_file;
 extern const char* tunable_pasv_address;
+extern const char* tunable_pasv_hostname;
 extern const char* tunable_listen_address;
 extern const char* tunable_user_config_dir;
 extern const char* tunable_listen_address6;
diff -up vsftpd-2.2.2/tunables.c.dyn_host vsftpd-2.2.2/tunables.c
--- vsftpd-2.2.2/tunables.c.dyn_host	2010-11-15 10:37:44.772026000 -0700
+++ vsftpd-2.2.2/tunables.c	2010-11-16 00:32:52.035039315 -0700
@@ -72,6 +72,7 @@ int tunable_force_anon_data_ssl;
 int tunable_mdtm_write;
 int tunable_lock_upload_files;
 int tunable_pasv_addr_resolve;
+int tunable_pasv_addr_dynamic;
 int tunable_userlist_log;
 int tunable_debug_ssl;
 int tunable_require_cert;
@@ -124,6 +125,7 @@ const char* tunable_anon_root;
 const char* tunable_local_root;
 const char* tunable_banner_file;
 const char* tunable_pasv_address;
+const char* tunable_pasv_hostname;
 const char* tunable_listen_address;
 const char* tunable_user_config_dir;
 const char* tunable_listen_address6;
@@ -209,6 +211,7 @@ tunables_load_defaults()
   tunable_mdtm_write = 1;
   tunable_lock_upload_files = 1;
   tunable_pasv_addr_resolve = 0;
+  tunable_pasv_addr_dynamic = 0;
   tunable_userlist_log = 0;
   tunable_debug_ssl = 0;
   tunable_require_cert = 0;
@@ -265,6 +268,7 @@ tunables_load_defaults()
   install_str_setting(0, &tunable_local_root);
   install_str_setting(0, &tunable_banner_file);
   install_str_setting(0, &tunable_pasv_address);
+  install_str_setting(0, &tunable_pasv_hostname);
   install_str_setting(0, &tunable_listen_address);
   install_str_setting(0, &tunable_user_config_dir);
   install_str_setting(0, &tunable_listen_address6);
diff -up vsftpd-2.2.2/vsftpd.conf.5.dyn_host vsftpd-2.2.2/vsftpd.conf.5
--- vsftpd-2.2.2/vsftpd.conf.5.dyn_host	2010-11-15 10:37:44.777025999 -0700
+++ vsftpd-2.2.2/vsftpd.conf.5	2010-12-13 17:22:51.733723842 -0700
@@ -361,6 +361,21 @@ option.
 
 Default: NO
 .TP
+.B pasv_addr_dynamic
+Set to YES if the hostname specified in the
+.BR pasv_hostname
+or
+.BR pasv_address
+option is associated with a dynamic IP address.
+This causes the hostname's address to be DNS resolved with each PASV command.
+The
+.BR pasv_hostname
+or
+.BR pasv_addr_resolve
+option must be used for this option to have any effect.
+
+Default: NO
+.TP
 .B pasv_enable
 Set to NO if you want to disallow the PASV method of obtaining a data
 connection.
@@ -955,10 +970,27 @@ Use this option to override the IP addre
 response to the PASV command. Provide a numeric IP address, unless
 .BR pasv_addr_resolve
 is enabled, in which case you can provide a hostname which will be DNS
-resolved for you at startup.
+resolved for you with the first PASV command. If the hostname is associated
+with a dynamic address, enable the
+.BR pasv_addr_dynamic
+option to have the address DNS resolved with each subsequent PASV command.
+If the
+.BR pasv_hostname
+option is used, this option is ignored.
 
 Default: (none - the address is taken from the incoming connected socket)
 .TP
+.B pasv_hostname
+Use this option to specify a hostname as an alternative to using the
+.BR pasv_address
+option in conjunction with the
+.BR pasv_addr_resolve
+option. If the hostname is associated with a dynamic address, enable the
+.BR pasv_addr_dynamic
+option to have the address DNS resolved with each PASV command.
+
+Default: (none)
+.TP
 .B rsa_cert_file
 This option specifies the location of the RSA certificate to use for SSL
 encrypted connections.