Topic: Client host rejected: rDNS/DNS validation failed. Please setup matching DNS

[Agent86]

Hi all,

For some email recipients such as craigslist etc. I get email failures.

failure notice:
Client host rejected: rDNS/DNS validation failed. Please setup matching DNS and rDNS records:

sale-6389XXXX@craigslist.org>:
66.150.243.3 does not like recipient.
Remote host said: 554 <unknown[70.XX.??.??]>: Client host rejected: rDNS/DNS validation failed. Please setup matching DNS and rDNS records: http://bind8nt.meiway.com/itsaDNSmess.cfm
Giving up on 66.150.243.3.

I've read via google and other forums regarding the subject as shown below:

You have to set up (or have your ISP set up) a PTR record for your mailserver's IP address that points back to the A record for your mailserver.

Does anyone know about this subject, and how to correct it.

And is this something I really have to do at my domain server, or do I do this from in SME server ??

Please advise
Thanks

[raem]

Agent86

You do it yourself if you have full control of your external DNS records, google for what is required,
or
you ask your ISP to do it for you.

[Agent86]

Agent86

You do it yourself if you have full control of your external DNS records, google for what is required,
or
you ask your ISP to do it for you.

Thanks for the reply.
I'll check this out.My domain hosting is purchased thru Yahoo, and I appear to have access to certain DNS settings.
My static IP is purchased thru Comcast.So I'm guessing I have to get Comcast to do it, because I don't have andy controls over that.
I'm a little confused about the subject, because thats what I get with my rDNS lookup, is showing as Comcast.
And,I don't believe I can do it thru yahoo or at least I don't see any setting in yahoo for setting up a rDNS or PTR etc.

I'll contact them both to find out what is what.
Thanks

[pfloor]

FYI: Where I am from, comcast can set your reverse DNS record but only on their business class accounts and they have to do it for you.  They have no mechanism in place for you to adjust any settings by yourself, you have to call their tech support and have them do it for you.

Good Luck

[Agent86]

FYI: Where I am from, comcast can set your reverse DNS record but only on their business class accounts and they have to do it for you.  They have no mechanism in place for you to adjust any settings by yourself, you have to call their tech support and have them do it for you.

Good Luck

I believe your right, and I'm pretty sure it's on their end and I don't think yahoo can do anything about this.

Thanks for the reply.

[Agent86]

Agent86

You do it yourself if you have full control of your external DNS records, google for what is required,
or
you ask your ISP to do it for you.

Well I've called comcast and they indicate that the rDNS and DNS are matching, which they should be on their end and Yahoo also says the same, however the problem appears to be that the Name server DNS is Yahoo, and the rDNS points back to comcast because of the IP address. So I'm not sure what to do, and Yahoo also indicated that the strict requirements of craigslist possibly won't allow or perhaps my SME server does not meet those requirements or that the headers won't meet the craigs servers requirements etc.
They also indicated that it could be something I can fix in the mail server which could cause this also.

I'm not sure what to do about it really. I've setup my client with a send mail using my comcast.net email address, but I don't want to have to do that, I wont webmail to send it for me.

Any other pointers on this would be great
Thanks

[janet]

Agent86

You can get Yahoo to whitelist your server so they accept mail from you.
Contact Yahoo tech support by email form.

You probably/possibly want escalated tech support from comcast to add entries for your domain name, but perhaps as pfloor says, they won't do what you want as your grade of service is too low.

[Agent86]

Agent86

You can get Yahoo to whitelist your server so they accept mail from you.
Contact Yahoo tech support by email form.

You probably/possibly want escalated tech support from comcast to add entries for your domain name, but perhaps as pfloor says, they won't do what you want as your grade of service is too low.

I'm not sure I understand your suggestion for Yahoo whitelist, I can send mail to Yahoo and all my other users have no problem with that either. The only reason I mentioned yahoo is because they are hosting my domain name so what they indicated to me is that their name servers / DNS and rDNS are the same, and comcast indicates the same thing as well. So I'm not sure who should really make changes Yahoo or Comcast or neither ? Yahoo also indicated that this could be some sort of setting in my email server that could cause this.
I have the email in SME set to resolve locally. Perhaps I should set it to resolve to the commercial DNS ?? would that do anything.

Or should I get comcast to set the PTR properly for my IP address they gave me ??

Also I've been playing around some more with this and also found that when sending mail thru comcast just using my standard client/thunderbird, and simple conifiguration for pop3 mail.comcast.net for incoming, and smtp.comcast.net for outgoing, then in this case I noticed craigslist also bounces back with the rDNS and DNS do not match error.
But, when sending mail with the same email address from comcast webmail I noticed that the mail appears to get sent without any return rDNS/DNS mismatch error.

????? I'm not sure what to think about this and why comcast webmail will send mail to craigsist but my client will not send mail to craigslist.

It would appear that it's not related to my email server and perhaps not even related to the PTR and rDNS setting and perhaps related to something totally different.

Also Yahoo webmail can send to craigslist no problems there either ?

Anyhow thats where I'm at with this so far any other tips would be great

This might not even be a SME topic Anymore at this point but I can't seem to confirm that. I really don't care about the comcast client but would love my SME email webmail to just be able to send mail to craigslist, however I'm not sure how to diagnose the problem or if it's up to comcast or yahoo to fix this.