Bug 33551 - System.Net.SmtpClient uses an invalid HELO name
Summary: System.Net.SmtpClient uses an invalid HELO name
Alias: None
Product: Class Libraries
Classification: Mono
Component: System (show other bugs)
Version: master
Hardware: PC Linux
: --- normal
Target Milestone: Untriaged
Assignee: Bugzilla
Depends on:
Reported: 2015-09-01 13:45 UTC by Thomas Jepp
Modified: 2015-12-27 03:02 UTC (History)
2 users (show)

See Also:
Is this bug a regression?: ---
Last known good build:


Description Thomas Jepp 2015-09-01 13:45:39 UTC
System.Net.SmtpClient uses Dns.GetHostName() to get the DNS name it uses for HELO.

On Windows (MS.NET) and Mono on Debian, this returns only the first part of the machine's domain name - but the name for HELO should be a FQDN.

An an example:
FQDN: test.example.com
Dns.GetHostName() returns "test"

SmtpClient should use Dns.GetHostEntry(Dns.GetHostName()).HostName to ensure it has a valid FQDN. This returns the correct full FQDN on MS.NET and Mono.
Comment 1 Thomas Jepp 2015-09-01 13:57:52 UTC
I've submitted a pull request: https://github.com/mono/mono/pull/2020
Comment 2 Miguel de Icaza [MSFT] 2015-12-27 03:02:15 UTC
This pull request was merged

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