This is a simple implementation of an LLMNR responder the ESP8266 Arduino package. Only support for advertizing a single hostname is currently implemented.
LLMNR is a very similar protocol to MDNS. The primary practical difference is that Windows systems (at least Windows 7 and later; perhaps earlier) support the protocol out-of-the-box, whereas additional software is required to support MDNS. However, Linux support is currently more complex, and MacOS X support appears non-existent.
- ESP8266WiFi library
- LLMNR support in your operating system/client machines:
- For Windows, support is already built in (in Windows 7 at least).
- For Linux, the systemd-resolve application supports LLMNR.
- For Mac OSX: Unknown; likely not supported.
- Install this repository using the instructions in the top-levle README.md file.
- Include the ESP8266LLMNR library in the sketch.
- Call the LLMNR.begin() method in the sketch's setup() function, and provide the hostname to advertize. This should not include any ".local" prefix.
- If ESP8266 AP mode is enabled, disabled, or the WiFi or AP configuration is changed, call LLMNR.notify_ap_change() after the change is made.
See the included LLMNR + HTTP server sketch for a full example.
- LLMNR implementations MUST support EDNS0 [RFC2671] and extended RCODE values. It is likely that this implementation does not; I have not read that RFC.
- LLMNR responders MUST support listening for TCP queries. This implementation does not.
- On receiving an LLMNR query, the responder MUST check whether it was sent to an LLMNR multicast addresses defined in Section 2. If it was sent to another multicast address, then the query MUST be silently discarded. This implementation makes no such check; it is hoped that the ESP8266 network stack filters out such packets since the code only joins the relevant multicast group and does not listen for unicast packets. This assumption may be invalid.
- Prior to sending an LLMNR response with the 'T' bit clear, a responder configured with a UNIQUE name MUST verify that there is no other host within the scope of LLMNR query propagation that is authoritative for the same name on that interface. This implementation performs no such verification.
- Prior to verifying that its name is UNIQUE, a responder MUST set the 'T' bit in responses. This implementation does not; it assumes that name is unique and responds with the 'T' bit clear in all cases.
- To verify uniqueness, a responder MUST send an LLMNR query with the 'C' bit clear, over all protocols on which it responds to LLMNR queries (IPv4 and/or IPv6). This implementation does not.
Copyright (C) 2017 Stephen Warren [email protected]
Based on: ESP8266 Multicast DNS (port of CC3000 Multicast DNS library) Version 1.1 Copyright (c) 2013 Tony DiCola ([email protected]) ESP8266 port (c) 2015 Ivan Grokhotkov ([email protected]) MDNS-SD Suport 2015 Hristo Gochkov Extended MDNS-SD support 2016 Lars Englund ([email protected])
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