How does Email from Brocade switches work?

[Tom Keck]

If anyone understands how SMTP mail from the switch works, please explain. It's not at all obvious how just identifying the DNS servers and domain name specifies an SMTP server. I can think of two possibilities:

1. The switch tries to get all the MX records from the DNS server for the zone that contains the domain and uses them to find an SMTP server.

2. SMTP server functionality is included in the switch firmware and it sends mail directly with the domain name suffix appended.

I tried placing an hp support call and posting this on the Brocade connect forum, but so far I haven't found anyone who knows how it works. I think Brocade has made some undocumented assumption about how DNS is setup that our site isn't meeting (such as no DNS zone dump access restrictions or all reverse address lookups are populated or that the switch domain name and email domain names are the same). If you understand which method switch email uses and what the assumptions are for it to actually work, please reply.

[Rob Leadbeater]

Hi Tom,

I've never actually used SMTP on a SAN switch but as FabricOS is based around Unix I would guess that option 1 is about right.

You could try using a network sniffer to see what DNS requests the switch is sending out on its ethernet port...

Cheers,

Rob

[Tom Keck]

I now understand how switch SMTP mail works so here's the answer to my own question:
From the switch root account use the following command to debug email.

echo "test" | sendmail -v your.email@yourdomain

the switch uses the DNS servers supplied to get the MX records for the smtp server for the domain in the email address.
The problem I had was that the server for our published email is outside our DMZ and can not be reached by the switch. (The domain you set on the switch is used to create the from address root@switchname.domain) Here's how to set a SMTP server (from Oliver at the Brocade Connect forum)

login to the switch as root and execute the following commands:

cd /etc/mail
ftp
(open and login to an ftp server)
put sendmail.cf

on the ftp server that you sent the file to, edit the sendmail.cf file.
find the line that says
# "Smart" relay host (may be null)
and replace the next line with the following:
DSyour_smtp_server's_FQN

go back to ftp on the switch:
get sendmail.cf
quit ftp
Re-execute the
echo "test" | sendmail -v
command to test the change.

Hope this helps someone else.

Tom

[Rick vonR]

For those of us whose company doesn't allow FTP you can use this method.

login to the switch as root and execute the following commands:

cd /etc/mail
sed 's/^DS/DS/g' sendmail.cf > sm
mv sm sendmail.cf