> For the complete documentation index, see [llms.txt](https://ivalexev.gitbook.io/rednote/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://ivalexev.gitbook.io/rednote/utility/service/llmnr-and-nbt-ns-5355-137.md).

# LLMNR & NBT-NS (5355-137)

Link-Local Multicast Name Resolution.

<details>

<summary>Protocol Information</summary>

Alternative method (along with NBT-NS) of host identification that can be used when [DNS](/rednote/utility/service/dns-53.md) fails. If a machine attempts to resolve a host but DNS resolution fails, typically, the machine will try to ask all other machines on the local network for the correct host address via LLMNR. LLMNR is based on the Domain Name System (DNS) format and allows hosts on the same local link to perform name resolution for other hosts. If LLMNR fails, NBT-NS will be used. NBT-NS identifies systems on a local network by their NetBIOS name.

</details>

## Port

<table data-header-hidden><thead><tr><th width="166">Port</th><th>Description</th></tr></thead><tbody><tr><td><mark style="color:green;"><strong>5355</strong></mark><strong> UDP</strong></td><td>LLMNR</td></tr><tr><td><mark style="color:green;"><strong>137</strong></mark><strong> UDP</strong></td><td>NBT-NS</td></tr></tbody></table>