On Wed, Feb 2, 2011 at 5:28 PM, David Lum <[email protected]> wrote:
> Does anyone know of a system I can telnet into
> enough to see that port 25 is open?
Are you looking to test to see if you can reach other MXes from your
MX, or to see if other MXes can reach your MX?
If the former, just pick any random MX. You can look them up easily
with DNS, e.g.:
nslookup -type=MX microsoft.com
Then "telnet foo 25" to one of the MXes you get. Do it from your own MX.
If the later:
You need access to a system that has unfiltered Internet
connectivity -- specifically, TCP port 25 outbound to arbitrary
addresses.
You generally won't find such well-advertised and free, because they
can be used just as easily by spammers. But a home computer with
SSH/RDP/etc. would generally work. Connect to that from your systems,
then do the MX test back. I've done this occasionally with my home PC
and work.
One caveat: Many ISPs filter TCP/25 outbound, especially for
residential users. If the home PC is on one of those, you can't use
it.
If you're really stuck for a host you can test your own MX with,
tell us your domain and/or IP address, and we can test it for you.
You're not really exposing much, since to receive mail you have to
publish an MX record and open TCP/25 inbound anyway.
-- Ben
~ Finally, powerful endpoint security that ISN'T a resource hog! ~
~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/> ~
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