Re: What's blocking Port 25?
No. I've still got my old server running. When I set
port forwarding on the router to point again to the
old box, it gets mail just fine.
In fact, a lot of the messages languishing on my ISP's
MTA find their way to the old box, no problem, when I
reset the router's port forwarding to it.
(I eventually want to set the old box up as a
dedicated firewall.)
gp--- Luke Kearney
<lukek@meibin.net> wrote:
>
> On Thu, 29 Jul 2004 21:39:44 -0700 (PDT)
> Griffin Palmer <griffjo@pacbell.net> spake thus:
>
> > This may be one for the firewalls list, but I'm
> not
> > entirely sure this is a firewall issue, or, at
> least,
> > *entirely* a firewall issue. I'm pretty sure it's
> not
> > an exim issue.
> >
> > I thought I'd see if there are any troubleshooting
> > suggestions from this obviously very experienced
> user
> > base, before trying more specialized lists.
> >
> > I've just installed testing/unstable on my
> machine.
> >
> > I'm running behind a NAT DSL router, with iptables
> on
> > my machine.
> >
> > I have my own domain, running its own DNS, smtp
> host,
> > http host, etc.
> >
> > I'm using exim 4.41, compiled from source, as my
> MTA.
> >
> > I was earlier running exim 3.36-11 on another box,
> > behind the same router, using identical port
> > forwarding. But in the fresh install on more
> robust
> > hardware, something has gone amiss.
> >
> > I'm pretty sure it's not exim. All the diagnostics
> > check out for exim. I can send from and reply to
> > local-domain addresses, using either mutt or mail.
> >
> > I can also send messages to the outside world. But
> > replies (or original messages) from the outside
> world
> > fall on deaf ears. Eventually, I get an "I've
> given up
> > trying" message from my ISP's MTA -- except in one
> > instance (more on that below).
> >
> > Here's where it gets confusing. Running nmap
> against
> > my machine from outside the domain shows it is
> > answering that Port 25 is closed. This even
> though,
> > using FireStarter, I've explicitly opened Port 25.
> >
> > I'm *certain* I've properly forwarded Port 25 to
> the
> > correct IP address for my new machine.
> >
> > Here's another oddity: Even though my machine
> replies
> > 'closed' to Port 25 scans, I got one error reply
> with
> > one message attempt from my ISP account that
> suggests
> > the port isn't *entirely* closed.
> >
> > Thinking I might have DNS configuration problems,
> I
> > tried sending a message to myself@123.457.789.012
> (my
> > user name and IP address substituted for this
> dummy
> > address). I didn't realize at the time you had to
> > configure exim to accept mail addressed in this
> > fashion.
> >
> > I got an error message back informing me that exim
> had
> > refused to forward the dotted-quad-addressed
> message
> > to my account on my host.
> >
> > So it seems as if *something* is getting through
> on
> > Port 25.
> >
> > It doesn't seem, though, that it's a matter of
> > messages reaching my host and then exim failing to
> > properly forward them locally: There are no
> > unforwarded messages languishing on exim's input
> > queue.
> >
> > Any troubleshooting ideas would be appreciated.
> >
> > Griff Palmer
>
> is it feasible that your ISP now filters inbound
> smtp possibly as an
> anti-spam or anti-virus measure?
>
> HTH
> LukeK
> --
> Luke Kearney <lukek@meibin.net>
>
>
> --
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