Bug 33551

Summary: System.Net.SmtpClient uses an invalid HELO name
Product: [Mono] Class Libraries Reporter: Thomas Jepp <tom>
Component: SystemAssignee: Bugzilla <bugzilla>
Severity: normal CC: miguel, mono-bugs+mono
Priority: ---    
Version: master   
Target Milestone: Untriaged   
Hardware: PC   
OS: Linux   
Tags: 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