diff --git a/Client.cpp b/Client.cpp
index 25012dcc..3423f170 100644
--- a/Client.cpp
+++ b/Client.cpp
@@ -126,10 +126,16 @@ void CClient::ReadLine(const CString& sData) {
 
 			return;  // Don't forward this msg.  ZNC has already registered us.
 		}
+	} else if (sCommand.Equals("CAP")) {
+		HandleCap(sLine);
+
+		// Don't let the client talk to the server directly about CAP,
+		// we don't want anything enabled that znc does not support.
+		return;
 	}
 
 	if (!m_pUser) {
-		// Only NICK, USER and PASS are allowed before login
+		// Only CAP, NICK, USER and PASS are allowed before login
 		return;
 	}
 
@@ -588,7 +594,7 @@ bool CClient::SendMotd() {
 }
 
 void CClient::AuthUser() {
-	if (!m_bGotNick || !m_bGotUser)
+	if (!m_bGotNick || !m_bGotUser || m_bInCap || IsAttached())
 		return;
 
 	m_spAuth = new CClientAuth(this, m_sUser, m_sPass);
@@ -771,3 +777,26 @@ CString CClient::GetNickMask() const {
 
 	return GetNick() + "!" + m_pUser->GetIdent() + "@" + sHost;
 }
+
+void CClient::RespondCap(const CString& sResponse)
+{
+	PutClient(":irc.znc.in CAP " + GetNick() + " " + sResponse);
+}
+
+void CClient::HandleCap(const CString& sLine)
+{
+	CString sSubCmd = sLine.Token(1);
+
+	if (sSubCmd.Equals("LS")) {
+		RespondCap("LS :");
+		m_bInCap = true;
+	} else if (sSubCmd.Equals("END")) {
+		m_bInCap = false;
+		AuthUser();
+	} else if (sSubCmd.Equals("REQ")) {
+		// No capabilities supported for now
+		RespondCap("NAK :" + sLine.Token(2, true).TrimPrefix_n(":"));
+	} else if (sSubCmd.Equals("LIST")) {
+		RespondCap("LIST :");
+	}
+}
diff --git a/Client.h b/Client.h
index d00a84d5..aafe6ce4 100644
--- a/Client.h
+++ b/Client.h
@@ -78,6 +78,7 @@ public:
 		m_bGotPass = false;
 		m_bGotNick = false;
 		m_bGotUser = false;
+		m_bInCap = false;
 		m_bNamesx = false;
 		m_bUHNames = false;
 		EnableReadLine();
@@ -127,11 +128,14 @@ public:
 	const CIRCSock* GetIRCSock() const;
 	CIRCSock* GetIRCSock();
 private:
+	void HandleCap(const CString& sLine);
+	void RespondCap(const CString& sResponse);
 
 protected:
 	bool                 m_bGotPass;
 	bool                 m_bGotNick;
 	bool                 m_bGotUser;
+	bool                 m_bInCap;
 	bool                 m_bNamesx;
 	bool                 m_bUHNames;
 	CUser*               m_pUser;
diff --git a/IRCSock.cpp b/IRCSock.cpp
index e9fd034f..9ae123ba 100644
--- a/IRCSock.cpp
+++ b/IRCSock.cpp
@@ -671,6 +671,9 @@ void CIRCSock::ReadLine(const CString& sData) {
 					}
 				}
 			}
+
+			// Don't forward any CAP stuff to the client
+			return;
 		}
 	}