One domain can't send email to another domain... but everything else is fine?!

suas

We're having an unusual problem with our email.

Someone at xyz.ie has been trying to send emails to us at suas.ie , but the emails aren't getting through. The sender is getting a "550 sorry, no mailbox here by that name (#5.1.1)" error, even though they are replying to a mail they have just received from person[at]suas.ie At Suas, all other emails seem to be arriving as expected and we have had no other reports of people getting bouncebacks.

Our setup is that we use Google Apps for our mail hosting. It has been working very well for a year and a half, and the MX records were not changed lately. This is what dnsstuff reports:
20 alt1.aspmx.l.google.com. [TTL=86400] IP=209.85.210.86 (No Glue) [TTL=293] [US]
20 alt2.aspmx.l.google.com. [TTL=86400] IP=209.85.212.57 (No Glue) [TTL=293] [US]
30 aspmx2.googlemail.com. [TTL=86400] IP=209.85.135.27 (No Glue) [TTL=2350] [US]
30 aspmx3.googlemail.com. [TTL=86400] IP=209.85.222.2 (No Glue) [TTL=2350] [US]
30 aspmx4.googlemail.com. [TTL=86400] IP=209.85.219.8 (No Glue) [TTL=2245] [US]
30 aspmx5.googlemail.com. [TTL=86400] IP=209.85.210.2 (No Glue) [TTL=2245] [US]
10 aspmx.l.google.com. [TTL=86400] IP=209.85.223.44 (No Glue) [TTL=293] [US]

In an effort to get to the bottom of it Google asked us (they are so slow to reply) for an incoming message with full headers. This is impossible since we don't get the emails.

A colleague came up with the smart idea of cc'ing an email from xyz.ie to a problem address at suas.ie and another domain... and then getting the headers from that other domain.

Great thinking, but when we tried it, the sender couldn't even send that email.

Outlook gave a send/receive error... it looks like it couldn't connect to the sending server. Attached. But only when trying to send to our domain!? All other emails from xyz.ie send normally.

Is there any way to track down where this blockage is occurring, why, and to do something about it?

suas

ooops, forgot to attach the error message last night.

Bear in mind, this error only happens with the senders outlook when they are trying to send to our domain. Very confusing.

Any advice appreciated!

aidan_walsh

Is there another address on your domain that the person can try mailing and see if it is specific to the account they are sending to, or to your service in general?

suas

Tried that, and no matter what address the person tries to email on the suas.ie domain, they get the same unusual error.

Initially, they were just getting a bounce back error message (I'll paste it in below), but then last night it changed to the 'unable to send' error in the attachment.

My feeling is that it's a problem with their SMTP server (I've emailed their hosting company), but I've no way to investigate or prove this.

From: System Administrator
Sent: 24 November 2009 12:53
To: 'xxxxxxx@suas.ie'
Subject: Undeliverable: Email issues

Your message did not reach some or all of the intended recipients.

Subject: FW: Email issues
Sent: 24/11/2009 12:53

The following recipient(s) could not be reached:

'xxxxxx@suas.ie' on 24/11/2009 12:53
- Hide quoted text -
550 sorry, no mailbox here by that name (#5.1.1)

Liam Byrne

suas wrote: »

ooops, forgot to attach the error message last night.

Bear in mind, this error only happens with the senders outlook when they are trying to send to our domain. Very confusing.

Any advice appreciated!

AFAIK that's a POP3 error ? 110 is the POP3 port, not the SMTP port.

I'd guess that her account credentials are wrong, so the combined "Send and Receive" task is failing on the "Receive", not on the "Send" ?

Also, it can depend on what antivirus she has installed, with some doing a "localhost" alias; if her credentials are correct, try using the IP address of the mail server instead of the name (McAfee used to have a major issue in this area).

suas

That's the quirky thing. Her account credentials are correct, since she can use outlook to send email successfully to other domains.

It's a head-wrecker!! As I say, I think the problem is with her sending server, she goes through her ISP. What test could I do to prove that, though?

Our mail is handled by Google Apps and I tested to see if she could send from xyz.ie to a different Google Apps account and she could, so the problem isn't a total block between her ISP and Google Apps, it's something specifc to our domain.

Apologies if my explanations are a little unclear, I'm kindof out of my depth and hence the requests for help.

Thanks for the ideas.

suas

Hurrah for Digiweb tech support and their sherlock holmes-like attitude. We don't even use them for our email, but they've come back with a very plausible explanation, which involves our old hosting company (which is also the company that xyz.ie are using for email).

I'll post a full explanation if indeed this is solution..

I now need to contact our old hosts quickly!

Sposs

Sounds like just conflicting dns records , thats why you should always let your hosting company know you have moved your domain name away so they can delete the domain records on their systems.

Dardania

Sposs wrote: »

Sounds like just conflicting dns records , thats why you should always let your hosting company know you have moved your domain name away so they can delete the domain records on their systems.

I wouldn't say that's the problem, as the old DNS host has the same records as the present one.

Although - can there be a problem if the old DNS server considers itself authoritive, when IEDR will point to a different DNS server?

Sposs

The old DNS will be authoritive for all mail coming through the old hosting providers mail servers, meaning the issue arises when an email is sent from the domain on it's new DNS to any other domain hosted by the old provider.

Dardania

so in theory it shouldn't be a problem, provided both zone files are the same?

Sposs

But how would both zones be the same if there set-up on two different providers? nameservers for old host are not going to be the same as new host.

Dardania

True...I was only considering the MX records, as they're certainly the same.

suas

I'm afraid I don't really understand the conversation about about zone files, as you can tell this is something that I know very little about!

In a nutshell, it's now fixed.

The old hosting company had been told we'd moved (back in February), and DNS settings had been adjusted (by someone that knew what they were doing!).

The problem apparently comes from the old host having a legacy record in their mail server (rcpthosts or something?) of our domain which meant that email sent by one of their customers to us couldn't get past their SMTP server. (the customer xyz.ie was using their hosts smpt server instead of their ISPs). I can't figure out why the problem took so long to occur - either the hosts restored some files from somewhere or xyz.ie changed how they send their mail.

I'm not going to get into a discussion about the old hosts, or mention them by name at all - other than to say how glad I am that we are no longer with them. It took 6 phone calls and upwards of 20 emails to get to the right person to delete the required files on their system. Then, when they did it, it wasn't done completely and had to be repeated.

It's now entirely fixed up, thanks to everyone for their help.

mneylon

Sposs wrote: »

The old DNS will be authoritive for all mail coming through the old hosting providers mail servers, meaning the issue arises when an email is sent from the domain on it's new DNS to any other domain hosted by the old provider.

That depends on the provider's configuration.

If you're running a large network you should be using resolvers AND authoritative nameservers, which would avoid this kind of issue entirely