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Contributor dpastern
Contributor

SMTP problems

OK, for the past week or so, I have been unable to send mail from the mail app on my iPad when on my home Optus NBN network.  

 

Some details...

 

I have set up an @ecn.net.au Email address (my own) on the mail app on iPad.  I am using mail.optusnet.com.au as the SMTP server (as I am on a Optus network when sending mail).  This has worked without issue up until a week ago.  

 

I am sending Emails to a @Yahoo.com.au Email address (my own).  

 

What have I tested so far?

 

I have sent a test Email from the iPad to my @ecn.net.au Email address without issue (that tells me that Optus is not barring non Optus domains from sending mail on the Optus SMTP servers).

 

I have checked my public IP address via whatismyip.com and conrirmed that it is not currently listed on any of the major RBLs.  

 

I have checked mail.optusnet.com.au to ensure that it is not listed on any of the major RBLs.

 

I checked my Yahoo mail settings and for some unknown reason, a fitler had been set up to block all mails from the @ecn.net.au realm.  This has been removed.  After this, I logged onto the webmail client for my @ecn.net.au address and successfully sent a test email to my @Yahoo.com.au address without issue.  So, I know the blocking filter has been removed.

 

After this, I resent the original messages from my iPad, but still have not received them (an hour later).  Other mail is coming into my Yahoo mail box after this without issue, so it is not an imcoming mail server issue at Yahoo's end imho.

 

I next hopped onto my Mac and opened up a UNIX shell and did a telent to mail.optusnet.com.au on port 25, issuing a HELO, then mail from (did a test optus address as my one has prolly been deleted when my original account was cancelled - note: I'm now using my brother in law's NBN connection at the same physical street address), then rcpt to (my yahoo.com.au address), then data, then told the Optus mail server to queue the mail by issuing a period (dot or full stop to normal non technical people).  Waited 5 minutes, nothing has been received.  Here is the transcript of the telnet session (with my personal details removed of course):

 

Macintosh:youtube melkor$ telnet mail.optusnet.com.au 25

Trying 211.29.132.250...

Connected to mail.optusnet.com.au.

Escape character is '^]'.

220 mail104.syd.optusnet.com.au ESMTP Postfix

helo optusnet.com.au

250 mail104.syd.optusnet.com.au

#mail from: edited@optusnet.com.au

250 2.1.0 Ok

#rcpt to: edited@yahoo.com.au

250 2.1.5 Ok

data

354 End data with <CR><LF>.<CR><LF>

test email

.

250 2.0.0 Ok: queued as EFCEE427305

 

Other tests conducted were disconnecting my iPhone from the local network and forcing it to use the Optus 4G connection, and then set it to wifi share (via Bluetooth) to my iPad.  This eliminates the public IP address of the home NBN connection as being the cause of the connectivity issues.  

 

So, either yahoo is blocking mail from the optusnet SMTP server, or my public IP address, OR, there is a mail routing issue at Optus' end.

 

Can someone (a level 3 tech) log onto the responsible mail server and test that they can ping (pop.mail.yahoo.com), traceroute (pop.mail.yahoo.com) and telnet to the Yahoo pop mail server address?  For the telnet test, you'll need to use these settings:

 

pop.mail.yahoo.com

 

port 995

 

I am curious to see whether the Optus SMTP server can a) ping, b) traceroute and c) telnet and successfully connect to the Yahoo pop server.  

 

Another thing that is worth testing is to see if you can telnet to pop.mail.yahoo.com on port 995 from your DNS server (the name server that provides the DNS resolution to your SMTP server(s)).  

 

Also, basic troubleshooting should have an Optus tech check the SMTP logs for my @Yahoo.com.au Email address (date: 11/11/2018, time between 10:30 and 11:59 PM AEST).  

 

I'm not sure mail application Optus is using to send mail (postfix, sendmail, qmail, Microsoft Exchange etc), but there should be a SMTP log file that can be parsed.  

 

A bit about me - my last job I was the sysadmin responsible for a small ISPs mail (Linux & Exchange), DNS (BIND), web (apache and Windows hosting) and SQL servers (mySQL and MS SQL)  (8 years) along with some network admin stuff (doesn't really interest me to be honest) and a bit of CISCO programming (again, doens't interest me much).  Overall, I have 15 years experience in IT, with experience in operating systems.  

 

I can provide my actual Email addresses to Optus technical staff if required.

 

I shall try and call and speak to a tech tomorrow after my brother in law gets home frmo work and authorises me on his account as the on site technician.  

 

edit: I just noticed that the Optus SMTP server greeted with a postfix, so that answers my question as to what you're using.

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30 Replies
Contributor dpastern
Contributor

Re: SMTP problems

I'll just add that I sent an Email to my @Yahoo.com.au address and CC'd in my @ecn.net.au address just now - ECN address received the mail just fine, yahoo mail nada.  

 

If anyone else has a @Yahoo.com.au Email address, can you successfuly send an Email via an Optus SMTP server to it?  

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Moderator Aman_B
Moderator

Re: SMTP problems

Hi @  dpastern -  So this just happens when connected via NBN? We don't var any emails as such and it should work.  Now to isolate the issue, I'd recommend  connecting so tome other NBN WiFI and check if this happens again. This will tell us if the issue is with your home network or the mail settings. I'd also recommend checking some of our settings Here  that could help as a guide. 


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Esteemed Contributor
Esteemed Contributor

Re: SMTP problems

Hey  I just gave it a go and like yourself I could send mail to my own domain but Yahoo did not recieve it. I expect a bounce at some stage but nothing has come through yet. The Optus IP I used is on Spamhaus. From what I understand there is no delisting service and contacting Yahoo may be the only option.

 

https://mxtoolbox.com/SuperTool.aspx?action=blacklist%3a49.184.192.97&run=toolpage

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Contributor dpastern
Contributor

Re: SMTP problems

No - when using 4G on my iPhone and testing it, I did not receive the Emails either. 

 

It is not the mail settings.  They've:

 

a) been unchanged from when they were working

 

and

 

b) are indeed correct (mail.optusnet.com.au; port 25, no username/password, no SSL)

 

I have helped thousands of customers set up their Email settings on iOS, PC, Mac and Linux devices over the years.  

 

The problem resides within the Optus infrastructure.  

 

I do not have access to another NBN connection to test, but my experience tells me it is not the connection or home network.  

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Contributor dpastern
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Re: SMTP problems

Thanks for testing.  It's been a week since my last Emails actually worked, and no bounce backs, so whilst possible, it's unlikely.  

 

Thanks for testing the RBL - in this case, your public IP address is listed on the Spamhaus RBL.  I have tested mine (106.71.106.50) and it is not.  Nor is mail.optusnet.com.au.  

 

49.184.192.97 belongs to Optus, and it is THEIR responsiblity to de-list the IP address from Spamhaus, or any other RBL.  I have a great deal of experience with RBLs and dealing with blacklists (it's what happens when you're responsible for managing 4 mail servers over an 8 year period).  

 

And Zenhouse does let you request a removal:

 

https://www.spamhaus.org/pbl/query/PBL1664493

 

of course, their reason that you need to be using SMTP authentication is utter BS.  Understand thar RBLs are a law unto themselves, they are much like the vigilantes of the Internet and should be bloody well banned and made illegal imho. 

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Esteemed Contributor
Esteemed Contributor

Re: SMTP problems

Hmm just tried again with a different subnet and it's blocked as well. Smiley LOL  I understand Spamhaus allows you to delist but I don't know if Yahoo even uses it. 

 

https://mxtoolbox.com/SuperTool.aspx?action=blacklist%3a49.184.167.180&run=toolpage

 

Edit: If your mail is not sending is there any reason you don't want to use your own mail server?

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Contributor dpastern
Contributor

Re: SMTP problems

It is not uncommon to see an entire range blocked by RBLs.  

 

Spamhaus, along with SORBS and Barracuda are major RBLs, most, if not all mail servers will subscribe to them.  Whilst I can't prove that Yahoo is using Spamhaus, I'm prettty confident that they are.  

 

as to using my own mail server, I'm not entirely sure what you mean there.  If you are on an Optus network, then you need to use an Optus SMTP server for all outgoing mail (to stop a thing called mail relaying).  If you're on Telstra, you use Telstra, etc.  If you're referring to using my own mail server, a) i'm too lazy to set one up at home, b) it shouldn't be necessary as I should be able to use Optus' SMTP servers as part of the network service that they provide (and they should work reliabily too!) and c) my own mail server would mean having to manage it etc, which for a private setup, is just a royal p.i.t.a.  I much prefer the path of least resistance.  d) I'd need access to the DNS zone file for the ecn.net.au to adjust the MX settings spf setup to allow my NBN Optus IP addresss as a permitted sender to relay mail for the @ecn.net.au domain.  ECN isn't going to allow this  😉  most mail servers will auto block mail that comes from an unauthorised IP address not permitted as a sender for said realm...

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Esteemed Contributor
Esteemed Contributor

Re: SMTP problems

Depending on your hosting environment it's a fairly simple process to run mail on another port. In my case its a matter clicking one button to run another instance of Exim on port 26. I think Plesk has a similar process and its something that has the added benefit of working with all isps. I understand and I agree that you shouldn't have to go to that extreme but it may be something to consider if you can't resolve the issues with Optus. Smiley Happy

 

https://kb.iweb.com/hc/en-us/articles/230243928-Enabling-an-instance-of-Exim-to-run-on-different-por...

 

https://talk.plesk.com/threads/opening-up-smtp-on-port-26.58809/

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Contributor dpastern
Contributor

Re: SMTP problems

Sorry, I wouldn't touch exim, sendmail or postfix (I'm a qmail type of guy).  😛

 

either way, I do not have a PC to set up a mail server, and I'm not going to waste time or money (for powering said PC)!  

 

It's just not a matter of setting up the mail server, or port forwarding, if you're sending mail on behalf of another domain, you really need to address the spf issues or you'll have a host (pun intended) of issues!

 

Either way, Optus is responsible for their SMTP servers and it is reasonable to expect for them to work, and if not, that they investigate and address the issues.  

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