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sjmarbu

.forward timing out on send

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I'm using a .forward file in my home directory on a MacOS X system to forward all of my mail to spamcop for filtering. Starting sometime late on Sunday, 4/3/2005, that forwarding operation stopped working.

When I checked the postfix log (I'm using a postfix mail server) I see lots of entries like:

00E0A22B436: to=<sjmarbu[at]spamcop.net>, orig_to=<junkbmw[at]gunsmoke.com>, relay=none, delay=67487, status=deferred (connect to mx2.spamcop.net[216.154.195.36]: Operation timed out)

I've checked my firewall config to make sure the usual mail ports are open (SMTP, POP).

I'm a relative newbie at configuring mail servers, and wonder if it's something on my end that's out of whack? There haven't been any changes to postfix in months, but could it be something else?

Or has there been a change at spamcop that could result in the timeouts?

TIA,

Scot

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No change at SpamCop that I've heard of. But you did choose to select the time of your problem starting as that of the start of Daylight Savings Time .... maybe nothing, but the coincidence is there ...

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No change at SpamCop that I've heard of.  But you did choose to select the time of your problem starting as that of the start of Daylight Savings Time .... maybe nothing, but the coincidence is there ...

26294[/snapback]

I was afraid that would be the answer.

Here are some more details:

I use dyndns.org to redirect traffic to my computer, which is assigned a dynamic IP number by SBC. From what I can gather, I shouldn't have to register an MX record for either domain that is hosted on that box, but...

If I send mail to myself at scot at marburger.com (a domain I don't host on that machine) it is forwarded by marburger.com to my computer and postfix successfully forwards it to spamcop.net. If, however, I send mail to myself at either scotmarburger.com or gunsmoke.com, both of which have traffic forwarded by dyndns.org to my computer, postfix fails to forward, and the postfix log shows the timeout error mentioned above.

Does that ring any bells?

TIA,

Scot

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Could someone have changed firewall rules to disallow SMTP traffic to 216.154.195.36 and possibly 216.154.195.53 (both of spamcop.net's incoming mailservers)?

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I believe I found the problem. Sometime over the weekend SBC started blocking port 25 on my portion of their network. Their tech support assert that the blocking has been in place for several months, but my experience contradicts this.

To overcome the blocking, I needed to configure Postfix to relay mail through the SBC mail server, which also requires authentication. Under MacOS X a program called Postfix Enabler makes this pretty easy, if you know the syntax for entry of the mail server name. It turns out that the name of the server must be surrounded with brackets [] in order for it to work, not only in the specification for the server name, but also where the authentication information is entered. So, for example, it would look something like this:

[sbcglobal.net.yahoo.com] this is the server name

[sbcglobal.net.yahoo.com] myusername[at]sbcglobal.net:mypassword this is the string to enter for the authentication configuration.

FWIW,

Scot

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That is interesting, I've had my port 25 blocked by my ISP, and their technical staff claimed the contrary. In fact they said naively, we are using the same port, why would we block yours. Nevertheless, after my inquiries they stopped the practice. Sounds like this may be a more widespread problem.

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Can anyone recommend free easy-to-use telnet clients for various OS's that can easily generate logs sufficient to tell an ISP "here's exactly what happens when I telnet to Port 25 on ISPmailserver.example.com" (and procedures/tips for doing so)?

For instance, in Windows, the default Microsoft Telnet defaults to a text-only interface that likes having echo off (which can be overcome with undocumented command line option "/set local_echo" or text interface command "set local_echo", either of which sets a permanent toggle which can be unset by using "unset" instead of "set") and clearing the screen at inopportune moments like begin of session (which can be overcome by capturing the info before terminating the command with "Enter" or "Return") and end of session (which can be overcome by using text interface command "open hostname [portnumber]", as in "open ISPmailserver.example.com 25"). To use text interface commands, open the text interface by just running "telnet" without a hostname.

I envision the answers being collated into a FAQ Entry.

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