---
title: NoResponseException
summary: API reference for NoResponseException.
status: draft
owner: <owner>
last_reviewed: 2026-07-23
library: SAIF.Framework.DNS
reference_type: package
---

# NoResponseException

`NoResponseException` is thrown when no UDP response is received from the target DNS server after all retry attempts have been exhausted.

## Purpose
- Signal to the caller that a DNS lookup failed at the transport level (no reply received), as opposed to a parsing failure.

## Context
- Namespace: `SAIF.Framework.DNS`
- Assembly/package: `SAIF.BOF.Framework.DNS`
- Base type: `SystemException`

## Public members
| Member | Signature | Purpose |
| --- | --- | --- |
| NoResponseException() | `public NoResponseException()` | Default constructor with no message or inner exception. |
| NoResponseException(Exception) | `public NoResponseException(Exception innerException)` | Constructs the exception wrapping an inner exception, with no message. |
| NoResponseException(string, Exception) | `public NoResponseException(string message, Exception innerException)` | Constructs the exception with a message and an inner exception. |

## Behavioral notes
- The class is marked `[Serializable]` and includes a `protected` deserialization constructor (`SerializationInfo`, `StreamingContext`) for binary serialization support.
- Thrown by `Resolver.UdpTransfer` (internal to `Resolver.Lookup`) after up to 2 retries fail to yield a matching-id UDP reply; enforces [BR-005](../../business-rules.md#br-005-udp-requests-are-retried-up-to-two-additional-times-before-failing).

## Sources
- SAIF.Framework.DNS\NoResponseException.cs