{Disarmed} Re: telnet on local LAN question

[Paul Allen Newell]

On 8/18/2011 9:07 PM, Craig White wrote:
> On Thu, 2011-08-18 at 20:47 -0700, Paul Allen Newell wrote:
>> [root at yoyo ~]# netstat -anp | grep ":25"
>> tcp        0      0 127.0.0.1:25                0.0.0.0:*
>> LISTEN      1510/sendmail: acce
>> [root at yoyo ~]# netstat -anp | grep ":23"
>> [root at yoyo ~]#
>> +++
>>
>> I'm staring at man netstat and the description of local address,
>> foreign address, and state ... but not certain what it really means in
>> context of your question regarding listening ... I think I am supposed
>> to assume that this output means 127.0.0.1:25 is listening to anything
>> sent from 0.0.0.0:* ?
> ----
> I believe that means that you can only connect to port 25 from localhost
> and not any other computer.
>
> It's been many years since I used sendmail (I heavily recommend postfix)
> but I think if you edit /etc/mail/sendmail.mc and find the section...
>
> dnl # The following causes sendmail to only listen on the IPv4 loopback
> address
> dnl # 127.0.0.1 and not on any other network devices. Remove the
> loopback
> dnl # address restriction to accept email from the internet or intranet.
> dnl #
> DAEMON_OPTIONS(`Port=smtp,Addr=127.0.0.1, Name=MTA')dnl
>
> and chnage the last line to
> dnl DAEMON_OPTIONS(`Port=smtp,Addr=127.0.0.1, Name=MTA')dnl
>
> and restart sendmail to enable it to listen on all your network
> interfaces.
>
> Note that you then have to edit /etc/mail/access to control who can
> 'relay' email (and restart sendmail again).
>
> also note that generally running your own smtp server requires you to
> have a dns server so you have an mx record so it becomes obvious which
> server receives e-mail for your domain.
>
> Craig
>
>
Craig:

Thanks, I found that line in sendmail.mc and think I understand what it 
is doing ... and what your suggestion do commenting it out will do. I've 
begun googling about /etc/mail/access and that's going to take some time.

Though this potentially solve the larger question of allowing email to 
be received on my 192.168.2.x LAN, I need to ask if you are implying 
that doing this in sendmail.mc et al means that I don't have to do 
anything with iptables for the mail / mailx issue?

And it still leaves me with a failure in my learning exercise about not 
being able to tell my machines that they should accept my "test telnet" 
from other machines in my LAN. I don't want to waste folks time on a 
test that I don't need, but I feel there is something about 
communication between machines that I am not getting ... and need to if 
I am going to consider a more elegant LAN setup

Paul