Postfix/Yahoo/SMTP Connection timed out

[redpaint]

Hello,

We're having a lot of problems connecting to Yahoo's mailservers. We can't telnet (times out) or traceroute (stops midway) to their EU mailserver mx-eu.mail.am0.yahoodns.net[188.125.69.79]. We can connect to non-eu Yahoo mailservers without any problem at all.

Our IP isn't blacklisted.

Yahoo have said they have fixed the problem but we still can't connect even after changing the outbound SMTP IP - the only thing we didn't do was change the PTR on the new IP so it didn't point back to the blocked IP - perhaps that's the problem?

There aren't any outbound firewall rules that I can see.

Is there any way ASL could be preventing emails from going out to this IP? If not is there anything we could do verify the problem is at their end.

Many thanks
Andy

[faris]

I've seen the type of error you seem to be describing (can't even telnet) from time to time. One incident lasted several days.

And while I would normally not care too much, BT (incumbent telco in the UK) uses Yahoo as its mail service provider for most types of account, and many of our customers use these types of addresses.

BT is moving away from Yahoo now, so I think things will improve.

I have to say that I've not seen any incidents like this recently though - it has been weeks if not months since the last time I saw it happen.

[redpaint]

Hi Faris,

Unfortunately this has been several weeks and despite Yahoo asserting the case has been resolved emails are still not being delivered. Any ideas on next steps?

Thanks
Andy

[mikeshinn]

Is there any way ASL could be preventing emails from going out to this IP?

Thank you for the question. No ASL wouldnt do this.

[faris]

You are lucky that Yahoo was willing to interact with you directly. I didn't get that far.

But as to what to do next....if they insist the problem is resolved, maybe what's happening is something different?
In our logs, I think it was the "....but connection died" issue as opposed to "...can't establish..." type of thing.

I can't remember exactly what happened with telnet. It was either that a connection could be made but then nothing happened no matter what, or there was no answer on port 25. The former, I think. I used the IP shown in the logs as the IP I connected to.

But there is one thing I do remember .... I used a different mailserver (not one of ours) and my test mail was delivered without any problem. I do not know if it used a different route. If it did then the problem may have been on a network level between us and yahoo as opposed to yahoo's mail servers.

Unfortunately, teeny tiny company trying to deal with megacorp results in nothing happening unless loads and loads of people all complain. It is a really difficult situation to resolve.

[mikeshinn]

Unfortunately this has been several weeks and despite Yahoo asserting the case has been resolved emails are still not being delivered. Any ideas on next steps?

I'd do two things:

1) disable all your firewall rules, and see if that fixes the issue - if it does you have a custom rule thats causing this

2) if #2 doesnt resolve the issue, I'd fire up a sniffer to see whats happening at layer 3. It could be a networking issue.