diff --git a/src/internal.c b/src/internal.c
index 4eb23e6..ccf0a13 100644
--- a/src/internal.c
+++ b/src/internal.c
@@ -1426,6 +1426,14 @@ static int GetInputText(WOLFSSH* ssh, byte** pEol)
         eol = WSTRNSTR((const char*)ssh->inputBuffer.buffer, "\r\n",
                        ssh->inputBuffer.length);
 
+        /* section 4.2 in RFC 4253 states that can be lenient on the CR for
+         * interop with older or undocumented versions of SSH */
+        if (!eol) {
+            WLOG(WS_LOG_DEBUG, "Checking for old version of protocol exchange");
+            eol = WSTRNSTR((const char*)ssh->inputBuffer.buffer, "\n",
+                       ssh->inputBuffer.length);
+        }
+
         if (eol)
             gotLine = 1;
 
@@ -2254,6 +2262,8 @@ static int DoKexInit(WOLFSSH* ssh, byte* buf, word32 len, word32* idx)
         }
 
         if (ret == WS_SUCCESS) {
+            byte SSH_PROTO_EOL_SZ = 2;
+
             strSz = (word32)WSTRLEN(sshProtoIdStr) - SSH_PROTO_EOL_SZ;
             c32toa(strSz, scratchLen);
             ret = wc_HashUpdate(&ssh->handshake->hash, enmhashId,
@@ -5339,6 +5349,7 @@ int DoProtoId(WOLFSSH* ssh)
     int ret;
     word32 idSz;
     byte* eol;
+    byte  SSH_PROTO_EOL_SZ = 1;
 
     if ( (ret = GetInputText(ssh, &eol)) < 0) {
         WLOG(WS_LOG_DEBUG, "get input text failed");
@@ -5367,6 +5378,9 @@ int DoProtoId(WOLFSSH* ssh)
         ssh->clientOpenSSH = 1;
     }
 
+    if (*eol == '\r') {
+        SSH_PROTO_EOL_SZ++;
+    }
     *eol = 0;
 
     idSz = (word32)WSTRLEN((char*)ssh->inputBuffer.buffer);
diff --git a/wolfssh/internal.h b/wolfssh/internal.h
index 0cf6253..6dbee1c 100644
--- a/wolfssh/internal.h
+++ b/wolfssh/internal.h
@@ -123,7 +123,6 @@ enum {
 #define SHA1_96_SZ 12
 #define UINT32_SZ 4
 #define SSH_PROTO_SZ 7 /* "SSH-2.0" */
-#define SSH_PROTO_EOL_SZ 2 /* Just the CRLF */
 #define AEAD_IMP_IV_SZ 4
 #define AEAD_EXP_IV_SZ 8
 #define AEAD_NONCE_SZ (AEAD_IMP_IV_SZ+AEAD_EXP_IV_SZ)