---
name: "Sisimai::Reason::HostUnknown"
section: "3pm"
platform: "linux"
package: "libsisimai-perl"
version: "5.3.0-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/Sisimai::Reason::HostUnknown"
---

# Sisimai::Reason::HostUnknown(3pm)

Bounce reason is "hostunknown" or not.

## NAME

Sisimai::Reason::HostUnknown - Bounce reason is "hostunknown" or not.

## SYNOPSIS

```
    use Sisimai::Reason::HostUnknown;
    print Sisimai::Reason::HostUnknown->match('550 5.2.1 Host Unknown');   # 1
```

## DESCRIPTION

`"Sisimai::Reason::HostUnknown"` checks the bounce reason is `"hostunknown"` or not. This class is called only `"Sisimai::Reason"` class.

This is the error that the domain part (Right hand side of `"@"` sign) of the recipient's email address does not exist. In many case, the domain part is misspelled, or the domain name has been expired. Sisimai will set `"hostunknown"` to the reason of the email bounce if the value of `"Status:"` field in a bounce mail is `5.1.2`.

```
    Your message to the following recipients cannot be delivered:
    <kijitora@example.cat>:
    <<< No such domain.
```

## CLASS METHODS

### "text()"

`text()` method returns the fixed string `"hostunknown"`.

```
    print Sisimai::Reason::HostUnknown->text;  # hostunknown
```

### "match(string)"

`match()` method returns `1` if the argument matched with patterns defined in this class.

```
    print Sisimai::Reason::HostUnknown->match('550 5.2.1 Host Unknown');   # 1
```

### "true(Sisimai::Fact)"

`true()` method returns `1` if the bounce reason is `"hostunknown"`. The argument must be `"Sisimai::Fact"` object and this method is called only from `"Sisimai::Reason"` class.

## AUTHOR

azumakuniyuki

## COPYRIGHT

Copyright (C) 2014-2018,2020,2021,2023,2024 azumakuniyuki, All rights reserved.

## LICENSE

This software is distributed under The BSD 2-Clause License.