diff --git a/src/global/mail_params.c b/src/global/mail_params.c

index 91c70f7..483613c 100644

--- a/src/global/mail_params.c

+++ b/src/global/mail_params.c

@@ -379,6 +379,8 @@ int     warn_compat_break_smtputf8_enable;

 int     warn_compat_break_chroot;

 int     warn_compat_break_relay_restrictions;

+bool    var_rhel_ipv6_normalize;

+

 /* check_myhostname - lookup hostname and validate */

 static const char *check_myhostname(void)

@@ -825,6 +827,7 @@ void    mail_params_init()

 	VAR_LONG_QUEUE_IDS, DEF_LONG_QUEUE_IDS, &var_long_queue_ids,

 	VAR_STRICT_SMTPUTF8, DEF_STRICT_SMTPUTF8, &var_strict_smtputf8,

 	VAR_ENABLE_ORCPT, DEF_ENABLE_ORCPT, &var_enable_orcpt,

+	VAR_RHEL_IPV6_NORMALIZE, DEF_RHEL_IPV6_NORMALIZE, &var_rhel_ipv6_normalize,

 	0,

     };

     const char *cp;

diff --git a/src/global/mail_params.h b/src/global/mail_params.h

index e4358ca..74459d9 100644

--- a/src/global/mail_params.h

+++ b/src/global/mail_params.h

@@ -3153,7 +3153,7 @@ extern char *var_local_rwr_clients;

   * EHLO keyword filter.

   */

 #define VAR_SMTPD_EHLO_DIS_WORDS	"smtpd_discard_ehlo_keywords"

-#define DEF_SMTPD_EHLO_DIS_WORDS	""

+#define DEF_SMTPD_EHLO_DIS_WORDS	"chunking"

 extern char *var_smtpd_ehlo_dis_words;

 #define VAR_SMTPD_EHLO_DIS_MAPS		"smtpd_discard_ehlo_keyword_address_maps"

@@ -4199,9 +4199,13 @@ extern int var_postlogd_watchdog;

 #define INFO_LOG_ADDR_FORM_NAME_INTERNAL	"internal"

 #define VAR_INFO_LOG_ADDR_FORM	"info_log_address_format"

-#define DEF_INFO_LOG_ADDR_FORM	INFO_LOG_ADDR_FORM_NAME_EXTERNAL

+#define DEF_INFO_LOG_ADDR_FORM	INFO_LOG_ADDR_FORM_NAME_INTERNAL

 extern char *var_info_log_addr_form;

+#define VAR_RHEL_IPV6_NORMALIZE	"rhel_ipv6_normalize"

+#define DEF_RHEL_IPV6_NORMALIZE	0

+extern bool var_rhel_ipv6_normalize;

+

 /* LICENSE

 /* .ad

 /* .fi

diff --git a/src/smtpd/smtpd.c b/src/smtpd/smtpd.c

index da7227f..53e640e 100644

--- a/src/smtpd/smtpd.c

+++ b/src/smtpd/smtpd.c

@@ -4334,6 +4334,7 @@ static int xclient_cmd(SMTPD_STATE *state, int argc, SMTPD_TOKEN *argv)

     SMTPD_TOKEN *argp;

     char   *raw_value;

     char   *attr_value;

+    const char *bare_value;

     char   *attr_name;

     int     update_namaddr = 0;

     int     name_status;

@@ -4481,15 +4482,31 @@ static int xclient_cmd(SMTPD_STATE *state, int argc, SMTPD_TOKEN *argv)

 		UPDATE_STR(state->addr, attr_value);

 		UPDATE_STR(state->rfc_addr, attr_value);

 	    } else {

-		neuter(attr_value, NEUTER_CHARACTERS, '?');

-		if (normalize_mailhost_addr(attr_value, &state->rfc_addr,

+		if (var_rhel_ipv6_normalize) {

+			neuter(attr_value, NEUTER_CHARACTERS, '?');

+		}

+		if ((var_rhel_ipv6_normalize &&

+		    normalize_mailhost_addr(attr_value, &state->rfc_addr,

 					    &state->addr,

-					    &state->addr_family) < 0) {

+					    &state->addr_family) < 0) ||

+		    (!var_rhel_ipv6_normalize &&

+			(bare_value = valid_mailhost_addr(attr_value, DONT_GRIPE)) == 0)) {

 		    state->error_mask |= MAIL_ERROR_PROTOCOL;

 		    smtpd_chat_reply(state, "501 5.5.4 Bad %s syntax: %s",

 				     XCLIENT_ADDR, attr_value);

 		    return (-1);

 		}

+		if (!var_rhel_ipv6_normalize) {

+		    UPDATE_STR(state->addr, bare_value);

+		    UPDATE_STR(state->rfc_addr, attr_value);

+#ifdef HAS_IPV6

+		    if (strncasecmp(attr_value, INET_PROTO_NAME_IPV6 ":",

+			    sizeof(INET_PROTO_NAME_IPV6 ":") - 1) == 0)

+			state->addr_family = AF_INET6;

+		    else

+#endif

+			state->addr_family = AF_INET;

+                }

 	    }

 	    update_namaddr = 1;

 	}

@@ -4569,17 +4586,25 @@ static int xclient_cmd(SMTPD_STATE *state, int argc, SMTPD_TOKEN *argv)

 		attr_value = SERVER_ADDR_UNKNOWN;

 		UPDATE_STR(state->dest_addr, attr_value);

 	    } else {

+		if (var_rhel_ipv6_normalize) {

 #define NO_NORM_RFC_ADDR		((char **) 0)

 #define NO_NORM_ADDR_FAMILY	((int *) 0)

-		neuter(attr_value, NEUTER_CHARACTERS, '?');

-		if (normalize_mailhost_addr(attr_value, NO_NORM_RFC_ADDR,

+			neuter(attr_value, NEUTER_CHARACTERS, '?');

+		}

+		if ((var_rhel_ipv6_normalize &&

+		    normalize_mailhost_addr(attr_value, NO_NORM_RFC_ADDR,

 					    &state->dest_addr,

-					    NO_NORM_ADDR_FAMILY) < 0) {

+					    NO_NORM_ADDR_FAMILY) < 0) ||

+		    (!var_rhel_ipv6_normalize &&

+			(bare_value = valid_mailhost_addr(attr_value, DONT_GRIPE)) == 0)) {

 		    state->error_mask |= MAIL_ERROR_PROTOCOL;

 		    smtpd_chat_reply(state, "501 5.5.4 Bad %s syntax: %s",

 				     XCLIENT_DESTADDR, attr_value);

 		    return (-1);

 		}

+		if (!var_rhel_ipv6_normalize) {

+			UPDATE_STR(state->dest_addr, bare_value);

+		}

 	    }

 	    /* XXX Require same address family as client address. */

 	}

@@ -4690,6 +4715,7 @@ static int xforward_cmd(SMTPD_STATE *state, int argc, SMTPD_TOKEN *argv)

     SMTPD_TOKEN *argp;

     char   *raw_value;

     char   *attr_value;

+    const char *bare_value;

     char   *attr_name;

     int     updated = 0;

     static const NAME_CODE xforward_flags[] = {

@@ -4808,15 +4834,22 @@ static int xforward_cmd(SMTPD_STATE *state, int argc, SMTPD_TOKEN *argv)

 		UPDATE_STR(state->xforward.addr, attr_value);

 	    } else {

 		neuter(attr_value, NEUTER_CHARACTERS, '?');

-		if (normalize_mailhost_addr(attr_value,

+		if ((var_rhel_ipv6_normalize &&

+		    normalize_mailhost_addr(attr_value,

 					    &state->xforward.rfc_addr,

 					    &state->xforward.addr,

-					    NO_NORM_ADDR_FAMILY) < 0) {

+					    NO_NORM_ADDR_FAMILY) < 0) ||

+		    (!var_rhel_ipv6_normalize &&

+			(bare_value = valid_mailhost_addr(attr_value, DONT_GRIPE)) == 0)) {

 		    state->error_mask |= MAIL_ERROR_PROTOCOL;

 		    smtpd_chat_reply(state, "501 5.5.4 Bad %s syntax: %s",

 				     XFORWARD_ADDR, attr_value);

 		    return (-1);

 		}

+		if (!var_rhel_ipv6_normalize) {

+		    UPDATE_STR(state->xforward.addr, bare_value);

+		    UPDATE_STR(state->xforward.rfc_addr, attr_value);

+		}

 	    }

 	    break;