diff --git a/command/channel_auth.cpp b/command/channel_auth.cpp
index 67ad8c7..f719452 100644
--- a/command/channel_auth.cpp
+++ b/command/channel_auth.cpp
@@ -19,7 +19,10 @@
         std::vector<uint8_t> errorPayload{IPMI_CC_REQ_DATA_LEN_INVALID};
         return errorPayload;
     }
-    uint8_t chNum = ipmi::convertCurrentChannelNum(request->channelNumber);
+    constexpr unsigned int channelMask = 0x0f;
+    uint8_t chNum = ipmi::convertCurrentChannelNum(
+        request->channelNumber & channelMask, getInterfaceIndex());
+
     if (!ipmi::isValidChannel(chNum) ||
         (ipmi::EChannelSessSupported::none ==
          ipmi::getChannelSessionSupport(chNum)) ||