diff --git a/CHANGES b/CHANGES
index 9aa3997..c1eaf68 100644
--- a/CHANGES
+++ b/CHANGES
@@ -204,6 +204,9 @@ corrections:
 
 	Fixed a few minor bugs with OpenSSL in configure and with messages
 
+	Socat did not work in FIPS mode because 1024 instead of 512 bit DH prime
+	is required. Thanks to Zhigang Wang for reporting and sending a patch.
+
 porting:
 	Red Hat issue 1020203: configure checks fail with some compilers.
 	Use case: clang
diff --git a/xio-openssl.c b/xio-openssl.c
index c17aa32..a031e35 100644
--- a/xio-openssl.c
+++ b/xio-openssl.c
@@ -1045,15 +1045,20 @@ int
    }
  
    {
-      static unsigned char dh512_p[] = {
-	 0xDA,0x58,0x3C,0x16,0xD9,0x85,0x22,0x89,0xD0,0xE4,0xAF,0x75,
-	 0x6F,0x4C,0xCA,0x92,0xDD,0x4B,0xE5,0x33,0xB8,0x04,0xFB,0x0F,
-	 0xED,0x94,0xEF,0x9C,0x8A,0x44,0x03,0xED,0x57,0x46,0x50,0xD3,
-	 0x69,0x99,0xDB,0x29,0xD7,0x76,0x27,0x6B,0xA2,0xD3,0xD4,0x12,
-	 0xE2,0x18,0xF4,0xDD,0x1E,0x08,0x4C,0xF6,0xD8,0x00,0x3E,0x7C,
-	 0x47,0x74,0xE8,0x33,
+      static unsigned char dh1024_p[] = {
+	 0xCC,0x17,0xF2,0xDC,0x96,0xDF,0x59,0xA4,0x46,0xC5,0x3E,0x0E,
+	 0xB8,0x26,0x55,0x0C,0xE3,0x88,0xC1,0xCE,0xA7,0xBC,0xB3,0xBF,
+	 0x16,0x94,0xD8,0xA9,0x45,0xA2,0xCE,0xA9,0x5B,0x22,0x25,0x5F,
+	 0x92,0x59,0x94,0x1C,0x22,0xBF,0xCB,0xC8,0xC8,0x57,0xCB,0xBF,
+	 0xBC,0x0E,0xE8,0x40,0xF9,0x87,0x03,0xBF,0x60,0x9B,0x08,0xC6,
+	 0x8E,0x99,0xC6,0x05,0xFC,0x00,0xD6,0x6D,0x90,0xA8,0xF5,0xF8,
+	 0xD3,0x8D,0x43,0xC8,0x8F,0x7A,0xBD,0xBB,0x28,0xAC,0x04,0x69,
+	 0x4A,0x0B,0x86,0x73,0x37,0xF0,0x6D,0x4F,0x04,0xF6,0xF5,0xAF,
+	 0xBF,0xAB,0x8E,0xCE,0x75,0x53,0x4D,0x7F,0x7D,0x17,0x78,0x0E,
+	 0x12,0x46,0x4A,0xAF,0x95,0x99,0xEF,0xBC,0xA6,0xC5,0x41,0x77,
+	 0x43,0x7A,0xB9,0xEC,0x8E,0x07,0x3C,0x6D,
       };
-      static unsigned char dh512_g[] = {
+      static unsigned char dh1024_g[] = {
 	 0x02,
       };
       DH *dh;
@@ -1066,8 +1071,8 @@ int
 	 }
 	 Error("DH_new() failed");
       } else {
-	 dh->p = BN_bin2bn(dh512_p, sizeof(dh512_p), NULL);
-	 dh->g = BN_bin2bn(dh512_g, sizeof(dh512_g), NULL);
+	 dh->p = BN_bin2bn(dh1024_p, sizeof(dh1024_p), NULL);
+	 dh->g = BN_bin2bn(dh1024_g, sizeof(dh1024_g), NULL);
 	 if ((dh->p == NULL) || (dh->g == NULL)) {
 	    while (err = ERR_get_error()) {
 	       Warn1("BN_bin2bn(): %s",
@@ -1362,7 +1367,6 @@ static bool openssl_check_peername(X509_NAME *name, const char *peername) {
    return openssl_check_name((const char *)text, peername);
 }
 
-/* retrieves certificate provided by peer, sets env vars containing
 /* retrieves certificate provided by peer, sets env vars containing
    certificates field values, and checks peername if provided by
    calling function */