Emails from Clients getting blocked from ISP's

[bjsteiger]

I have several client's whose emails are being blocked from ISP's and I am trying to understand why this is happening?

Does anybody have any suggestions

bjs

 

[eWebtricity]

Depends on alot of things. You have to investigate each problem individually. Your clients could be blocked becuase:

1. Their domain is blacklisted by an RBL that the recipient is using, in this case it's a little out of your control because your client's domain is listed by a third party organization. Futhermore you can't stop the recipient from using the RBL. The client can request the recipient to "whitelist" their domain to avoid this problem. The client could then pursue requesting their domain be removed from the RBL.

2. Your IP address of your server hosting your client could be blocked by an ISP or RBL. You can contact the ISP or RBL and request your IP be removed. Verizon and several others went on a rampage a few months ago blocking large portions of IP address ranges to cut down on their spam intake. It was at the risk of alienating their customers ....I still don't understand this move.

3. A virus running on the recipient network could be creating havoc with email, but this is out of your control.

4. Misconfiguration of the recipient mail server

5. Your MX records and reverse DNS could be misconfigured

We find that 99% of the email delivery complaints from our clients are beyond our control. We do our best to assist them in tracking down the problem and help them resolve it or educate them on what to do.

 

[Whistler]

Originally posted by bjsteiger
I have several client's whose emails are being blocked from ISP's and I am trying to understand why this is happening?

In order to help - you need to tell us - what is blocked? When your clients relay (send) mails via SMTP through your server or through their ISPs SMTP server?

What error do they get?

 

[bjsteiger]

Here is what I started to find out from one of my clients -- they are sending out emails and they are not bouncing back but the receiver is not getting them.

I started to do some digging and my server's IP is based in Germany so I am suspecting that this person's company is blocking outside of the US IP's

How common is this because I have seen this a few other times?

bjs

 

[pdreissen]

Kundenserver ?
They are listed in blacklists very much!

 

[Whistler]

You still haven't told us if your users uses your server to send mail thru? (SMTP) or their ISP?

What s the IP of your server and whats the domain they are trying to send mail thru?

 

[bjsteiger]

I'm sorry - I must have missed the question.

Yes, they use my server to send email

bjs

 

[Whistler]

Your server IP? Have you been listed as open mail relay? Listed as spammer?

 

[bjsteiger]

My IP is: 82.165.177.79

And yesterday I had run a report for an open rely through an outside service and they found no open ports.

Because my IP is based out of Germany and yet most of my customers are in the US...could they be blocking because of that?

bjs

 

[Whistler]

Oki According to http://www.dnsstuff.com/tools/ip4r.ch?ip=82.165.177.79 you're not listed in any spam blacklist - that's good!

I guess your customers are sending from known spamming IPs or hole spam-segments of IPs (or just dynamic assigned ip adresses -many servers block theese also).

But I think your customers (or you) should investigate by writing to the admins of servers not allowing your customers to relay mail to them, what MAPS filter they are using...

 

[jamesyeeoc]

Originally posted by bjsteiger
My IP is: 82.165.177.79

And yesterday I had run a report for an open rely through an outside service and they found no open ports.

Because my IP is based out of Germany and yet most of my customers are in the US...could they be blocking because of that?

bjs

It is possible. Most of my servers have large/entire countries outside the US blocked due to high spam rates. I'm sure there are other hosting admins here in the US who have done the same.