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Is relay.plus.net ok?

philipb
Dabbler
Posts: 12
Registered: ‎21-10-2011

Is relay.plus.net ok?

Is relay.plus.net ok at the moment?
I've not received a few emails sent via it Sat and today (Sun), so I tried the trick of sending one via telnet so I could see all the status messages and everything was "250" (OK) ending with "Mail accepted for delivery" - but nothing showed up at the non-Plusnet recipient.
It was server avasout05, if that's any help. The recipient is working ok with other senders.
EDIT: Ah, I'm wondering if the recipient's domain has been blocked by the spam filter?
9 REPLIES
Superuser
Superuser
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Registered: ‎22-08-2007

Re: Is relay.plus.net ok?

philipb
Dabbler
Posts: 12
Registered: ‎21-10-2011

Re: Is relay.plus.net ok?

I tried self -> (domain + cc:self) and neither received anything.
Then self -> (self + cc:domain) and self got the message but the domain didn't.
Then domain -> (domain + cc:self) and domain got the message but self didn't.
- from which I'm concluding that both accounts work properly, but Plusnet doesn't like the domain and won't send or receive from it for some reason.
The domain is registered to me, and shows as neutral on SenderBase. My router sends a syslog email to it once per day and for alerts - it's possible it might have sent a burst at some point which may have caused Plusnet to think something's amiss. <Wonders?>
EDIT: Just done SenderBase on my IP address, and it's coming back Email Rep: Poor, blacklisted on pbl.spamhaus.org.
Disconnected ADSL and re-connected for a new IP address, same Poor and blacklist.
Is the problem that Spamhaus have stuck some Plusnet hosts on their blacklist?
Superuser
Superuser
Posts: 13,038
Thanks: 4,332
Fixes: 26
Registered: ‎22-08-2007

Re: Is relay.plus.net ok?

HI,
I'm a bit confused here...
Quote from: philipb
EDIT: Ah, I'm wondering if the recipient's domain has been blocked by the spam filter?
Quote from: philipb
I tried self -> (domain + cc:self) and neither received anything.

In each of the above is "domain" the same domain?
Is that domain hosted by PlusNet?
Note that the relay will check the validity of the domain - see http://community.plus.net/forum/index.php/topic,143240.msg1263111.html#msg1263111 - if there is an issue with the domain's configuration, the email will not be sent.
philipb
Dabbler
Posts: 12
Registered: ‎21-10-2011

Re: Is relay.plus.net ok?

Yes, same domain - and no, hosted by another provider.
It looks like there's a SpamHaus PBL Advisory for lots of Plusnet IP addresses: "not meeting our policy for IP addresses permitted to deliver unauthenticated 'direct to mx' email to PBL users".
My router and this computer use relay.plus.net unauthenticated SMTP on port 25, I wonder if that's why stuff sent out to my external domain is being ignored?
Superuser
Superuser
Posts: 13,038
Thanks: 4,332
Fixes: 26
Registered: ‎22-08-2007

Re: Is relay.plus.net ok?

Unlikely.  It is not your IP address which is doing the sending, its relay.plus.net
The advisories you are looking at more likely refers to people running their own relay servers on PlusNet IP addresses.  Note that relay.plus.net is NOT in the block list.
It would be worth changing your configuration to use authenticated SMTP connection on port 587 WITHOUT SSL.
philipb
Dabbler
Posts: 12
Registered: ‎21-10-2011

Re: Is relay.plus.net ok?

Tried shifting to 587, but no luck.
It's weird, I can send unauthenticated via relay to hotmail fine, but not to my own domain. No errors, just nothing is received.
And I can send from my domain to hotmail, and hotmail to my domain ok.
So it looks like it's just Plusnet that has an issue with my domain - afaict.
Thanks for your help, Townman - It's one of those weird 'not really a problem' problems that's not worth losing sleep over. It might clear up - if not I'll raise a ticket in a week or so.
Cheers!
Superuser
Superuser
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Registered: ‎06-04-2007

Re: Is relay.plus.net ok?

Quote from: philipb
It looks like there's a SpamHaus PBL Advisory for lots of Plusnet IP addresses: "not meeting our policy for IP addresses permitted to deliver unauthenticated 'direct to mx' email to PBL users".

That's entirely normal (for all ISPs) and reflects that dynamic IP addresses are not expected to run mail transfer agents (MTAs) which send mail directly to a third-party MTA. The SpamHaus PBL is a Policy Block List and not a blacklist.
Mail from dynamic IPs has to be sent via a relay (relay.plus.net in the case of Plusnet) which can authenticate the source, then sends it to the destination MTA. It is the IP of relay.plus.net that should be checked against the PBL (if desired) and it won't be on it. If the receiving MTA is doing checks on the hops up to relay.plus.net it is mis-configured.
David
philipb
Dabbler
Posts: 12
Registered: ‎21-10-2011

Re: Is relay.plus.net ok?

That's interesting, thanks!
Community Gaffer
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Registered: ‎04-04-2007

Re: Is relay.plus.net ok?

Quote from: philipb
So it looks like it's just Plusnet that has an issue with my domain - afaict.

I'd expect an immediate 5xx rejection from the relays if there we were blocking the sending of messages to your domain.
For the inbound messages that's aren't arriving in your Plusnet mailbox, try disabling the 'Discard Obvious Spam' option in your spam settings and see if that makes any difference.
Only other thought I have, is that your domain takes advantage of some sort of mail forwarding service (does it?) meaning there'd be more than just the sender/recipient to consider.

Bob Pullen
Plusnet Product Team
If I've been helpful then please give thanks ⤵