diff --git a/compat.h b/compat.h
new file mode 100644
index 0000000..16cf282
--- /dev/null
+++ b/compat.h
@@ -0,0 +1,71 @@
+/* $OpenBSD: compat.h,v 1.42 2008/09/11 14:22:37 markus Exp $ */
+
+/*
+ * Copyright (c) 1999, 2000, 2001 Markus Friedl.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef COMPAT_H
+#define COMPAT_H
+
+#define	SSH_PROTO_UNKNOWN	0x00
+#define	SSH_PROTO_1		0x01
+#define	SSH_PROTO_1_PREFERRED	0x02
+#define	SSH_PROTO_2		0x04
+
+#define SSH_BUG_SIGBLOB		0x00000001
+#define SSH_BUG_PKSERVICE	0x00000002
+#define SSH_BUG_HMAC		0x00000004
+#define SSH_BUG_X11FWD		0x00000008
+#define SSH_OLD_SESSIONID	0x00000010
+#define SSH_BUG_PKAUTH		0x00000020
+#define SSH_BUG_DEBUG		0x00000040
+#define SSH_BUG_BANNER		0x00000080
+#define SSH_BUG_IGNOREMSG	0x00000100
+#define SSH_BUG_PKOK		0x00000200
+#define SSH_BUG_PASSWORDPAD	0x00000400
+#define SSH_BUG_SCANNER		0x00000800
+#define SSH_BUG_BIGENDIANAES	0x00001000
+#define SSH_BUG_RSASIGMD5	0x00002000
+#define SSH_OLD_DHGEX		0x00004000
+#define SSH_BUG_NOREKEY		0x00008000
+#define SSH_BUG_HBSERVICE	0x00010000
+#define SSH_BUG_OPENFAILURE	0x00020000
+#define SSH_BUG_DERIVEKEY	0x00040000
+#define SSH_BUG_DUMMYCHAN	0x00100000
+#define SSH_BUG_EXTEOF		0x00200000
+#define SSH_BUG_PROBE		0x00400000
+#define SSH_BUG_FIRSTKEX	0x00800000
+#define SSH_OLD_FORWARD_ADDR	0x01000000
+#define SSH_BUG_RFWD_ADDR	0x02000000
+#define SSH_NEW_OPENSSH		0x04000000
+
+void     enable_compat13(void);
+void     enable_compat20(void);
+void     compat_datafellows(const char *);
+int	 proto_spec(const char *);
+char	*compat_cipher_proposal(char *);
+
+extern int compat13;
+extern int compat20;
+extern int datafellows;
+#endif