Hi, I have just received a 'phone call from a trusted source. His e-mails to me have been rejected due to the new implementation of blocking dynamic IP addresses, as reported on the Service Announcement page. He works from a .co.uk website. Does this mean that replies from ALL such websites will be blocked ? Otherwise what do I do to ensure  e-mails from trusted sources get through?

Hi there,

It's not really clear what you mean by 'all such websites' without knowing how the trusted source's email systems are set up or how their systems are configured. This certainly wouldn't affect everybody with a .co.uk domain name!!

We have basically begun rejecting email that originates from IP addresses that are registered as dynamic or have suspicious rDNS entries. It's important to note that this may also include statically assigned IP addresses that are considered dynamic by the Internet registry responsible for the allocation of such addresses.
http://en.wikipedia.org/w..._IP#IP_address_allocation
http://www.ripe.net/info/ncc/index.html

If the email is legitimate then the most likely reason for its rejection is the fact that the sender will be attempting to deliver the email from a private smtp mail server instead of through their Internet Service Provider. If this is the case then it is recommended that you contact the sender of the email to ask that they use a 'smart-host' or 'smtp connector' so that emails to your address (or all PlusNet addresses if you do not have your own domain) are sent using their ISPs mail servers instead of from their own IP:-
http://en.wikipedia.org/wiki/Smart_host

If this is not possible and you are confident that the rejected email it genuine and standards compliant then you can forward the bounced message to abuse@plus.net so we can look at the possibility of whitelisting it. Should you do this, it is advised that you includes a bit of background detail explaining what problem is being experienced. You will also need to contain the full headers of the failed delivery notification you received:-
http://www.plus.net/suppo...ail_troubleshooting.shtml

Please be aware that you may not receive a dedicated reply from abuse.plus.net although any request will be considered in full and whitelisted where appropriate (whitelisting will prevent these emails from getting rejected):-
http://en.wikipedia.org/w...itelist#E-mail_whitelists

We expect that most of these rejections will be due to poor configuration of the senders systems in which case the mail is being rejected as it should.

Slightly confused here.

We have a very simple setup.  Netgear ADSL router connecting us to the internet which is firewalled and NAT'd up nicely.  Behind this we have our three office computers plus a Small Business Server 2003 running Exchange.

Exchange is picking up our emails using the built-in POP connector as we didn't see any need to have emails directly downloaded to us but we have some users anyway who simply use Outlook Express to pick up the occasional email they may be sent on our domain (hosted by PN also).

We're sending emails, on the whole, without problems, but did have two instances yesterday when we received this message about using a dynamic IP address problem.  The IP address on our server is manually configured and our PlusNet IP address is statically assigned.

Forgive the naivety but is there something we should do to stop these errors cause we're quite happy with the way everything was working and don't really want to have to change too much if we can help it now we've finally got everything running smoothly.

I believe this is because PlusNet declare their ADSL IPs as from a Dynamic range.  Thus, ISPs that block incoming mail from dynamic IPs will block your messages.

PlusNet now do the same (block mail from dynamic IPs), so I guess people running their own mail servers may be affected when emailing PlusNet domains.

Unless I've misunderstood.

Hi there,

These bits of my previous reply are of relevance...


Basically, your IP can still get rejected even if it is static. Statis IPs that ISPs assign customers are normally asigned by the registry from dynamic address space.


To get around it the sender would basically configure their email server to send email to our addresses (ie. plus.com, .force9.co.uk etc.) via their ISPs outgoing mailserver.


Was this people sending to you or you sending to others? We are only enforcing this on our inbound mail delivery platform. Did the rejection message contain our abuse email address?

We're on PlusNet so are using the standard PlusNet SMTP server to send all mails.  Our domain is also hosted by PlusNet.

The domain we have had problems with is hosted by Fasthosts.

However, the message undelierable message came back to us from PlusNet's mail server with the message about rejecting the email because of dynamic addressing and suggesting we contact the abuse account if we believed this to be in error.

By and large everything else is going ok and we resent the email earlier and it went through but this is probably cause it used a different mail server at PN's end.

Still not too sure what's happened here. Perhaps you could PM me the full headers of the rejected report.

1. You sent an email from a PN hosted domain via relay.plus.net to a Fasthosts hosted domain and received the bounced message back to the PN address?

2. You sent an email from the Fasthosts hosted domain via relay.plus.net to your PN address and received the bounced message back to the Fasthosts address?

3. You sent an email from the Fasthosts hosted domain via a third party or another ISP's mail server and received the bounced message back to the Fasthosts address?

Which (if any) of the above is true in your case. 1 and 2 should not happen AIUI, whereas 3 might.

Based on my limited experience of the impact of the new dynamic IP measures - namely:

1. Incoming mail from a customer - a trusted source who uses Zen Internet as their ISP;
2. Test loopback mail sent to myself (from my forwarding domain which has never had these problems before)

all gets bounced by PlusNet, my assessment would be that this measure has been brought in too hastily.

I have no idea yet how many genuine emails I'm losing because people don't understand the bounce message or know how to contact me otherwise. Even if they do understand, what chance do they have of communicating this to their ISP and getting them to change their mail configuration?

Very unhappy.

you may want to try what I have done to solve the problem.

That is to move my company's email away from Plusnet to an ISP that allows us to email properly. It really does work

Bob - after a couple of retries the email went through ok so I guess it went using a mail server that hasn't yet been updated with the new features.  AT this point we deleted the original error message so I don't have it at the moment.

If we have the problem again in the near future I will resend.  As the mail serevrs are upgraded in turn anyway I suspect we may see this problem more and more as the work pregresses.

a longstanding client of mine cannot now send me mails they are a major uk healthcare provider and this is causing major problems for me, telephone support was 'not really our problem' get your 'major' client to change the way they send emails or use a 'hotmail' account, at this moment i dont know how many other people are having problems mailing me, after an hour on phone to clients IT support they have sent plusnet bounced mail, hopefully this will get them white listed very annoyed  at the loss of todays work

I am amazed that Free-online have implemented this with no notice whatsoever that I have seen. I have had several clients call today to say their email is bouncing back.  Frankly they are not going to got through all that has been suggested to be able to send me email.  They will just go somewhere else.!!!!  We have 20 -30 new enquiries every day and if those emails bounce  they are just going to think we dont exist anymore.

Frankly I would rather get all the email sent to us and do the spam filtering myself  - CA anti spam work great!

Sorry Free- online but I think you cocked up on this one after giving us 10 years of great service.

I'm reading this thread and feeling very confused as I can't find any service status announcements relating to this subject -- can someone help please ?

The planned maintenance post of this work is here:-

http://usertools.plus.net...us/archive/1189789775.htm

I'm having exactly the same problem with the email bounces, with a very important client who uses BT openworld.

It simply is not on to introduce this change and then expect me to tell a client that if he wants to contact me he has to use the FAX.

The are lot of small businesses who don't have dedicated IT staff and we have to bumble along as best they can. the easiest thing probably to change ISP.

People can PM me the headers (complete with bounces) and I can look into things for them.

Especially interested in these, and anything from Fasthosts domains:



In the majority of cases I have seen I can see why the mail has been blocked. Before PM'ing me it would be worth trying the following in Windows...

You will need the IP address from the rejection report (the one it says has been refused)

Click Start > Run, type cmd and click OK


You can see here that the mail server that tried to hand the email to us has the IP address 209.85.50.70 that maps to ev1s-209-85-50-70.ev1servers.net


However the reverse is not true. ev1s-209-85-50-70.ev1servers.net does *not* map back to 209.85.50.70. This is very bad practice and what the work was intended to identify.

As I say though, I'm happy to look into examples customers have because we shouldn't be blocking mail from reputable sources.