diff --git a/build/parsePreamble.c b/build/parsePreamble.c
index ac3d9159e7..c6898dda43 100644
--- a/build/parsePreamble.c
+++ b/build/parsePreamble.c
@@ -643,17 +643,27 @@ static void specLog(rpmSpec spec, int lvl, const char *line, const char *msg)
  * @param allowedchars	string of permitted characters
  * @return		RPMRC_OK if OK
  */
-rpmRC rpmCharCheck(rpmSpec spec, const char *field, const char *allowedchars)
+rpmRC rpmCharCheck(rpmSpec spec, const char *field,
+		   const char *allowedchars,
+		   const char *allowedfirstchars)
 {
     const char *ch;
     char *err = NULL;
     rpmRC rc = RPMRC_OK;
 
+    if (allowedfirstchars && !(risalnum(*field) ||
+			       strchr(allowedfirstchars, *field))) {
+	rasprintf(&err, _("Illegal char '%c' (0x%x)"),
+		  isprint(*field) ? *field : '?', *field);
+    }
+
     for (ch=field; *ch; ch++) {
+	if (ch==field && allowedfirstchars) continue;
 	if (risalnum(*ch) || strchr(allowedchars, *ch)) continue;
 	rasprintf(&err, _("Illegal char '%c' (0x%x)"),
 		  isprint(*ch) ? *ch : '?', *ch);
     }
+
     for (ch=field; *ch; ch++) {
 	if (strchr("%{}", *ch)) {
 	    specLog(spec, RPMLOG_WARNING, field,
@@ -775,7 +785,8 @@ static rpmRC handlePreambleTag(rpmSpec spec, Package pkg, rpmTagVal tag,
     switch (tag) {
     case RPMTAG_NAME:
 	SINGLE_TOKEN_ONLY;
-	if (rpmCharCheck(spec, field, ALLOWED_CHARS_NAME))
+	if (rpmCharCheck(spec, field,
+			 ALLOWED_CHARS_NAME, ALLOWED_FIRSTCHARS_NAME))
 	   goto exit;
 	headerPutString(pkg->header, tag, field);
 	/* Main pkg name is unknown at the start, populate as soon as we can */
@@ -785,7 +796,7 @@ static rpmRC handlePreambleTag(rpmSpec spec, Package pkg, rpmTagVal tag,
     case RPMTAG_VERSION:
     case RPMTAG_RELEASE:
 	SINGLE_TOKEN_ONLY;
-	if (rpmCharCheck(spec, field, ALLOWED_CHARS_VERREL))
+	if (rpmCharCheck(spec, field, ALLOWED_CHARS_VERREL, NULL))
 	   goto exit;
 	headerPutString(pkg->header, tag, field);
 	break;
@@ -1111,7 +1122,7 @@ int parsePreamble(rpmSpec spec, int initialPackage)
 	    goto exit;
 	}
 
-	if (rpmCharCheck(spec, name, ALLOWED_CHARS_NAME))
+	if (rpmCharCheck(spec, name, ALLOWED_CHARS_NAME, flag == PART_SUBNAME ? NULL : ALLOWED_FIRSTCHARS_NAME))
 	    goto exit;
 	
 	if (!lookupPackage(spec, name, flag, NULL))
diff --git a/build/parseReqs.c b/build/parseReqs.c
index 4df0deb013..a2eb64fe5e 100644
--- a/build/parseReqs.c
+++ b/build/parseReqs.c
@@ -57,7 +57,7 @@ static rpmRC checkDep(rpmSpec spec, char *N, char *EVR, char **emsg)
             rasprintf(emsg, _("Versioned file name not permitted"));
             return RPMRC_FAIL;
         }
-        if (rpmCharCheck(spec, EVR, ALLOWED_CHARS_EVR))
+        if (rpmCharCheck(spec, EVR, ALLOWED_CHARS_EVR, NULL))
             return RPMRC_FAIL;
 	if (checkSep(EVR, '-', emsg) != RPMRC_OK ||
 	    checkSep(EVR, ':', emsg) != RPMRC_OK ||
@@ -278,7 +278,8 @@ rpmRC parseRCPOT(rpmSpec spec, Package pkg, const char *field, rpmTagVal tagN,
 	    goto exit;
 
 	if (nametag == RPMTAG_OBSOLETENAME) {
-	    if (rpmCharCheck(spec, N, ALLOWED_CHARS_NAME)) {
+	    if (rpmCharCheck(spec, N,
+			     ALLOWED_CHARS_NAME, ALLOWED_FIRSTCHARS_NAME)) {
 		rasprintf(&emsg, _("Only package names are allowed in "
 				   "Obsoletes"));
 		goto exit;
diff --git a/build/rpmbuild_internal.h b/build/rpmbuild_internal.h
index 39a9c916f6..e824c9fcd3 100644
--- a/build/rpmbuild_internal.h
+++ b/build/rpmbuild_internal.h
@@ -19,6 +19,7 @@
 #undef HTDATATYPE
 
 #define ALLOWED_CHARS_NAME ".-_+%{}"
+#define ALLOWED_FIRSTCHARS_NAME "_%"
 #define ALLOWED_CHARS_VERREL "._+%{}~^"
 #define ALLOWED_CHARS_EVR ALLOWED_CHARS_VERREL "-:"
 #define LEN_AND_STR(_tag) (sizeof(_tag)-1), (_tag)
@@ -382,7 +383,9 @@ int parseList(rpmSpec spec, const char *name, int stype);
  * @return              RPMRC_OK if OK
  */
 RPM_GNUC_INTERNAL
-rpmRC rpmCharCheck(rpmSpec spec, const char *field, const char *allowedchars);
+rpmRC rpmCharCheck(rpmSpec spec, const char *field,
+		   const char *allowedchars,
+		   const char *allowedcharsfirst);
 
 typedef rpmRC (*addReqProvFunction) (void *cbdata, rpmTagVal tagN,
 				     const char * N, const char * EVR, rpmsenseFlags Flags,