[nos-bbs] SMTP gateway

Mon Jul 28 18:49:05 EDT 2014

Thanks for the comments. Bob, before your message, I tried smtp trace 5 and got a nice trace. I found an e-mail to a gmail address first tried a gmail address and failed. Then it found a mail server from an ISP that is a parent to my ISP and it accepted the mail. I’ll pursue Michael’s suggestion of a dedicated mail server at my location or in the area so I can be certain of where mail is handled.

Jerry, N0MR

From: Boudewijn (Bob) Tenty 
Sent: Monday, July 28, 2014 4:29 PM
To: TAPR xNOS Mailing List 
Subject: Re: [nos-bbs] SMTP gateway

>From the jnos manual...

smtp trace [<value>]

Displays or sets the trace flag in the SMTP client, allowing you to watch SMTP's 
conversations as it delivers mail. Zero (the default) disables tracing. A trace 
value of 1 just enables the "new mail for n5knx from mailto:k5arh at w5ddl.ampr.org". 
Larger values produce more voluminous trace output.
73,

Bob VE3TOK

On 14-07-28 01:53 PM, Lakenet wrote:

  Michael, 

  Thank you for the note. I failed to mention that my Linux JNOS machine is located behind a Netscreen NS5GT firewall that blocks all but trusted incoming mail on port 25. That blocks the thousands of spam mails that would otherwise come in daily. Is there any trace or other parameter that I can set in JNOS to monitor outgoing SMTP traffic so I can see how and where outgoing SMTP traffic is going? I'm not a network person so I learn by lots of reading and trial and error. I will look into a mail server that I can run on the Linux machine and I have a couple of mentors that can help. 

  Jerry, N0MR 

  -----Original Message----- From: Michael E Fox - N6MEF 
  Sent: Monday, July 28, 2014 12:13 PM 
  To: 'TAPR xNOS Mailing List' 
  Subject: Re: [nos-bbs] SMTP gateway 

  JNOS already uses SMTP so it doesn't require a gateway.  But ... 

  -- The SMTP code in JNOS is very old and I've seen it do a couple things 
  (like pipelining when that option has not been negotiated) that aren't quite 
  correct by today's standards 
  -- The SMTP code in JNOS has no security mechanisms 

  So, if you are sending SMTP messages to or receiving SMTP messages from any 
  other machine that you don't trust 100% (this includes anything on the 
  Internet and probably the rest of 44-net) then you should configure 'smtp 
  gateway' to the address of a mail server you do trust. 

  For example, here is one way to do it:  Each of the linux machines that runs 
  JNOS in our network is also running a mail server.  JNOS is configured with 
  'smtp gateway' set to the linux IP address.   The linux mail server 
  configuration performs a dozen or more security checks on incoming mail 
  connections from other machines, including:  DNS lookups, blacklist lookups, 
  relay lookups, network-based lookups, spam detection, virus scanning, and 
  more.  It also performs some outbound checks to make sure JNOS has not be 
  compromised.  If your mail server is exposed to the Internet and you monitor 
  the mail logs on such a machine, you'll find that it will be hit with relay 
  or spam or virus attempts multiple times per hour.  But the gateway rejects 
  all of that (hopefully!), protecting the JNOS system. 

  Some home/SOHO routers may have something simple built into their software 
  which lets them protect you from some attacks.  Consult you're router's 
  documentation for details.  Perhaps Google or Yahoo or others provide a free 
  service.  Postini (now part of Google, ugh!) and others provide paid 
  services.  For details on how to set up your own, more comprehensive 
  solution, consult the documentation for your preferred mail server software: 
  sendmail, postfix, exim, ... 

  Finally, the JNOS release notes provide some details about extra 'smtp 
  gateway' options that were added a few versions ago. 

  Michael 
  N6MEF 

  -----Original Message----- 
  From: nos-bbs-bounces at tapr.org [mailto:nos-bbs-bounces at tapr.org] On Behalf 
  Of Lakenet 
  Sent: Monday, July 28, 2014 9:12 AM 
  To: TAPR xNOS Mailing List 
  Subject: [nos-bbs] SMTP gateway 

  I have always set SMTP gateway to none not knowing how to use that gateway. 
  Recently I read a reflector post that the gateway should be set to the 
  address of the home router I assume to route unroutable mail out into the 
  internet. I understand that any packet mail with no route to deliver would 
  go to the SMTP queue. So I entered a gmail address from within JNOS for a 
  test and the mail did get to the recipient. I did not see anything on the 
  monitor. How does this operation run? Does ampernet have some type of mail 
  handler? Does anyone know if there is something written to explain this 
  operation or can someone type me a simple explanation. 

  Thank you, 

  Jerry, N0MR 

  _______________________________________________ 
  nos-bbs mailing list 
  nos-bbs at tapr.org 
  http://www.tapr.org/mailman/listinfo/nos-bbs 

  _______________________________________________ 
  nos-bbs mailing list 
  nos-bbs at tapr.org 
  http://www.tapr.org/mailman/listinfo/nos-bbs 

--------------------------------------------------------------------------------
_______________________________________________
nos-bbs mailing list
nos-bbs at tapr.org
http://www.tapr.org/mailman/listinfo/nos-bbs
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.tapr.org/pipermail/nos-bbs_lists.tapr.org/attachments/20140728/2a64b19f/attachment.html>