Mail delivery to Craigslist fails

Just checked with my upstream and he states that he made the changes well over a week ago and I tried it again today and I am still running into the same problem which I think is also tying into my other issue with the MTA reputation being poor on my box. Anyhow it looks like I need to do some more reading.

Anyhow this is the link that CL sent me to have more information:

http://www.craigslist.org/about/help/rdns_failure

I wish there was a "DNS for Dummies" book out there

Neal
 
Its still the same thing you got going on.

Resloving [74.124.206.98]..
[74.124.206.98] [www.dxmhosting.com]

Resloving [www.dxmhosting.com]..
[www.dxmhosting.com] [74.124.204.2]

and

[cp.dxmhosting.com]..
[cp.dxmhosting.com] [74.124.206.98] which is correct

--

Looks like your upstream didn't change it after all, or not correctly.

He needs to set 74.124.206.98 to cp.dxmhosting.com.

Then everything should be fine.
 
Looks right to me:

Code: 
[root@super2 ~]# dig -x 74.124.206.98

; <<>> DiG 9.3.6-P1-RedHat-9.3.6-4.P1.el5_4.2 <<>> -x 74.124.206.98
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 51815
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;98.206.124.74.in-addr.arpa.    IN      PTR

;; ANSWER SECTION:
98.206.124.74.in-addr.arpa. 38400 IN    PTR     cp.dxmhosting.com.

;; Query time: 387 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Tue Sep 28 13:20:40 2010
;; MSG SIZE  rcvd: 75

[root@super2 ~]# dig cp.dxmhosting.com

; <<>> DiG 9.3.6-P1-RedHat-9.3.6-4.P1.el5_4.2 <<>> cp.dxmhosting.com
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 39748
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;cp.dxmhosting.com.             IN      A

;; ANSWER SECTION:
cp.dxmhosting.com.      14400   IN      A       74.124.206.98

;; Query time: 191 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Tue Sep 28 13:20:53 2010
;; MSG SIZE  rcvd: 51

There may be some residual dns caching hurting you right now. Give it a few more days.
 
Yes it's right now. If you ask me a bit of a coincidence, after a week it's not working, then you e-mail again and a moment later it all of a sudden it does work ;)

He could also just be telling the truth tho :)
 
I just tested and some nameservers return cp.dxmhosting.com while others return www.dxmhosting.com.

While either should be okay (RFCs don't require that an rDNS entry match the forward entry, many email admins (including the gujys who admin for Craigslist, obviously) make an extra requirement: they require that the domain name returned by the rDNS lookup, when resolved, resolves to the same IP#.

So it appears that either your upstream contact has two entries in rDNS for 74.124.206.98, or you've got some leftover caching going on. I presume the latter because running:
Code: 
$ dig -x 74.124.206.98 +trace
shows that ns1.corporatecolo.com and ns2.corporatecolo.com (the authoritative nameservers) are returning cp.dxmhosting.com.

I use google nameservers, and they're returning www.dxmhosting.com, with a remaining time-to-live of 27,603 seconds (a bit under 8 hours).

So I suggest you check this 8 hours from now:
Code: 
dig @8.8.4.4 -x 74.124.206.98
and see what you get. If you still get www.dxmhosting.com, then google is picking up the wrong information; please post the entire reply if it's not pointing to cp.dxmhosting.com.

Notes to everyone: I checked emailsl from Neal to ascertain that his emails are in fact coming from where he things they are, and I've checked both paths (my logs) and mail headers.

Code: 
$ dig @ns1.corporatecolo.com -x 74.124.206.98 +short
cp.dxmhosting.com.
$ dig -x 74.124.206.98 +short
www.dxmhosting.com.

The latter is using googlenameservers. The former is a direct query of the authoritative nameservers.

Jeff
 
jlasman said:
I use google nameservers, and they're returning www.dxmhosting.com, with a remaining time-to-live of 27,603 seconds (a bit under 8 hours).
Click to expand...

Interesting:

Code: 
[root@super2 ~]# dig @8.8.4.4 -x 74.124.206.98

; <<>> DiG 9.3.6-P1-RedHat-9.3.6-4.P1.el5_4.2 <<>> @8.8.4.4 -x 74.124.206.98
; (1 server found)
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 38338
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;98.206.124.74.in-addr.arpa.    IN      PTR

;; ANSWER SECTION:
98.206.124.74.in-addr.arpa. 35453 IN    PTR     cp.dxmhosting.com.

;; Query time: 31 msec
;; SERVER: 8.8.4.4#53(8.8.4.4)
;; WHEN: Tue Sep 28 14:09:49 2010
;; MSG SIZE  rcvd: 75
 
Thanks guys! Additionally I added an A record for cp (as a subdomain, after I realized I overlooked a reply from another gent) and mails are going through to CL now. Hopefully this resolves the problem for one of my other clients as well who was having an awful time sending out emails as well to various locations.
 
floyd said:
Interesting:

Code: 
[root@super2 ~]# dig @8.8.4.4 -x 74.124.206.98

; <<>> DiG 9.3.6-P1-RedHat-9.3.6-4.P1.el5_4.2 <<>> @8.8.4.4 -x 74.124.206.98
; (1 server found)
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 38338
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;98.206.124.74.in-addr.arpa.    IN      PTR

;; ANSWER SECTION:
98.206.124.74.in-addr.arpa. 35453 IN    PTR     cp.dxmhosting.com.

;; Query time: 31 msec
;; SERVER: 8.8.4.4#53(8.8.4.4)
;; WHEN: Tue Sep 28 14:09:49 2010
;; MSG SIZE  rcvd: 75
Click to expand...
Very interesting:
Code: 
dig @8.8.4.4 -x 74.124.206.98

; <<>> DiG 9.7.0-P1 <<>> @8.8.4.4 -x 74.124.206.98
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 23242
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;98.206.124.74.in-addr.arpa.    IN      PTR

;; ANSWER SECTION:
98.206.124.74.in-addr.arpa. 25474 IN    PTR     www.dxmhosting.com.

;; Query time: 47 msec
;; SERVER: 8.8.4.4#53(8.8.4.4)
;; WHEN: Tue Sep 28 11:37:10 2010
;; MSG SIZE  rcvd: 76
Google is no doubt using multiple servers, geographically dispersed, with the same IP#. And it's obviously causing issues.

Jeff
 
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