Index: pjsip/include/pjsip/sip_config.h
===================================================================
--- a/pjsip/include/pjsip/sip_config.h	(revision 6050)
+++ b/pjsip/include/pjsip/sip_config.h	(working copy)
@@ -1190,6 +1190,20 @@
 #   define PJSIP_AUTH_CACHED_POOL_MAX_SIZE	(20 * 1024)
 #endif
 
+
+/**
+ * Specify whether the cnonce used for SIP authentication contain digits only.
+ * The "cnonce" value is setup using GUID generator, i.e:
+ * pj_create_unique_string(), and the GUID string may contain hyphen character
+ * ("-"). Some SIP servers do not like this GUID format, so this option will
+ * strip any hyphens from the GUID string.
+ *
+ * Default is 1 (cnonce will only contain digit characters).
+ */
+#ifndef PJSIP_AUTH_CNONCE_USE_DIGITS_ONLY
+#   define PJSIP_AUTH_CNONCE_USE_DIGITS_ONLY	1
+#endif
+
 /*****************************************************************************
  *  SIP Event framework and presence settings.
  */
Index: pjsip/src/pjsip/sip_auth_client.c
===================================================================
--- a/pjsip/src/pjsip/sip_auth_client.c	(revision 6050)
+++ b/pjsip/src/pjsip/sip_auth_client.c	(working copy)
@@ -396,7 +396,23 @@
 
 	/* Create cnonce */
 	pj_create_unique_string( cached_auth->pool, &cached_auth->cnonce );
+#if defined(PJSIP_AUTH_CNONCE_USE_DIGITS_ONLY) && \
+    PJSIP_AUTH_CNONCE_USE_DIGITS_ONLY!=0
+	if (pj_strchr(&cached_auth->cnonce, '-')) {
+	    /* remove hyphen character. */
+	    int w, r, len = pj_strlen(&cached_auth->cnonce);
+	    char *s = cached_auth->cnonce.ptr;
 
+	    w = r = 0;
+	    for (; r < len; r++) {
+		if (s[r] != '-')
+		    s[w++] = s[r];
+	    }
+	    s[w] = '\0';
+	    cached_auth->cnonce.slen = w;
+	}
+#endif
+
 	/* Initialize nonce-count */
 	cached_auth->nc = 1;