We are receiving the following error message 80% of the time when sending out emails. There was a SMTP communication problem with the recipient's email server. Please contact your system administrator. <mail.server.com #5.5.0 smtp;553-mail rejected because your IP is in DUL. See> We recently changed our external IP address as we've moved to a new location, but all changes such as PTR records have been updated accordingly. I've been given the recommendation to test using Telnet, which I'm able to do. Are we missing some configuration during our transition to the new IP address? I've been recommended to use a smarthost, but we would like to control our own email server. ~berry

On Thu, 24 Jun 2010 21:45:01 +0000, berryguru wrote: > > >We are receiving the following error message 80% of the time when sending out emails. > >There was a SMTP communication problem with the recipient's email server. Please contact your system administrator. <mail.server.com #5.5.0 smtp;553-mail rejected because your IP is in DUL. See> > >We recently changed our external IP address as we've moved to a new location, but all changes such as PTR records have been updated accordingly. I've been given the recommendation to test using Telnet, which I'm able to do. > >Are we missing some configuration during our transition to the new IP address? I've been recommended to use a smarthost, but we would like to control our own email server. "DUL" = Dial Up List. Your IP address in in som DNSBL. See if http://www.mxtoolbox.com can discover which one. Once you find out which one you'll have to get yourself unlisted. You may have to get your ISP involved if your P address is a static assignment and the reason your in a DNSBL is because they think it's in a range of dynamically assigned addresses. --- Rich Matheisen MCSE+I, Exchange MVP --- Rich Matheisen MCSE+I, Exchange MVP

Hi Rich, That was actually one of the first things we did, and MX Tools came up clean. I tried a few other tools online and they came up clean too. I'm really stumped as to what's causing this error. Everything seems to check out okay! Any other thoughts? ~berry

On Fri, 25 Jun 2010 04:15:15 +0000, berryguru wrote: >That was actually one of the first things we did, and MX Tools came up clean. I tried a few other tools online and they came up clean too. I'm really stumped as to what's causing this error. Everything seems to check out okay! Any other thoughts? Now it's time to use a free e-mail account and contact the admin for the other domain. Or visit their web site and find a general telephone number and ask to speak wth whoever it is that uns the e-mail system, or the IT director/manager/vp/etc. Use whois to find the administrative and technical contacts for the domain -- call them. If they're protected, call the domain registrar and explain the problem, or find the ISP using their IP address and start there. E-mail's convenient, but that thing on your desk with 12 buttons still works. :-) --- Rich Matheisen MCSE+I, Exchange MVP --- Rich Matheisen MCSE+I, Exchange MVP

The severity of this issue goes beyond one or two people we can't communicate with. We are talking over 70% of emails are getting bounce backs. Something isn't right, whether it be our configuration (which nothing has changed, except the external IP) or something else. If this problem involved only one or two domains, I would simply ask them to add us to there whitelist. But this goes beyond that, this is definitely something more serious. I don't see many solutions, none at that matter to this #5.5.0 smtp;553-mail rejected because your IP is in DUL. See> error message. Somebody has had to of come across this problem and found a solution. I mean nothing has changed, except my external IP address. I just don't understand! ~berry

On Fri, 25 Jun 2010 22:25:18 +0000, berryguru wrote: >The severity of this issue goes beyond one or two people we can't communicate with. We are talking over 70% of emails are getting bounce backs. Something isn't right, whether it be our configuration (which nothing has changed, except the external IP) or something else. If this problem involved only one or two domains, I would simply ask them to add us to there whitelist. So instead of finding out what's actually causing the problem you want to do what? The chances are that whatever DNSBL or reputation server you're listed in it's going to be common to lots of the other domains, too. Ask one admin what DNSBL or reputation server they're using and you know where to start to get unlisted. And, since it's a new IP, I'd enlist the ISP in this. They'll know the domain name used by the previous owner and that might give you some information. >But this goes beyond that, this is definitely something more serious. I don't see many solutions, none at that matter to this #5.5.0 smtp;553-mail rejected because your IP is in DUL. See> error message. Somebody has had to of come across this problem and found a solution. I mean nothing has changed, except my external IP address. I just don't understand! ~berry How about putting your IP address in your answer? Spell it out if your worried. "One two three dot six dot fortynine dot ten" is pretty obvious to a human but it's not something a spider will pick up. --- Rich Matheisen MCSE+I, Exchange MVP --- Rich Matheisen MCSE+I, Exchange MVP

Hi berryguru, Any update for your issue? Agree with Rich's suggestion, it is good procedure to resolve your problem. Regards! gavin

Hey Gavin! Sorry I didn't get an update posted sooner, but I've resolved the problem. Rich was correct! I did a bit more tracing one morning and came across the following site: http://www.mail-abuse.com/enduserinfo_dul.html I emailed the following address For DUL inquiries, email dul@mail-abuse.com and requested our IP be delisted. I was informed that the reason for the listing was their records indicated our IP as dynamic. Once the request was sent, the responded within 12 hours. Hope that link and email helps others that come across the problem. It's is definitely a show stopper for companies. Cheers mates!! And thanks for the direction and advice. ~berry