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Old 18th November 2008, 16:25
rasjavita rasjavita is offline
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Default Postfix and 550 Reverse DNS lookup failed for host error

Hi all.

The problem is with mail accounts of an ISP (wanadoo).

When i send mail to any email address from wanadoo,orange,etc (all are the same ISP) the mails are returned with this error in my logs:

server refused to talk to me: 550 Reverse DNS lookup failed for host XX.XXX. (port 25)

I don't know if I have more problems, but I need to resolv this first. The IP address of my server is incomplete only the first and second octets appear.

I think the mails are retuned because the other server receive an incomplete IP from my server.

I try several combinations with "mynetwoks and mynetworks_style" in Postfix but nothing changes.

Any idea.


Last edited by rasjavita; 18th November 2008 at 16:27.
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Old 18th November 2008, 22:33
marpada marpada is offline
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Your IP must have a reverse DNS record, check your IP in this site


You have to configure correctly the reverse zone for your domain, if you manage your own zones.
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Last edited by marpada; 13th May 2011 at 02:56.
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Old 19th November 2008, 02:26
rasjavita rasjavita is offline
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I made the test at http://www.ipchecking.com/.

General information on XX.XXX.XX.XX:

IP address: XX.XXX.XX.XX
Host name: cliente-XXXXX.iberbanda.es (This is my ISP's name)
Country: SPAIN SPAIN Flag

RBL (Real-Time Blocking List) lookup on XX.XXX.XX.XX:
SPAMCOP - (SpamCop Blocking List): Not Found
SBL (Spamhaus Block List): Not Found
XBL (Spamhaus eXploits Block List"): Not Found
DSBL (Distributed Server Boycott List): Not Found
CBL (Composite Blocking List): Not Found
NJABL (Not Just Another Blocklist): Not Found
SORBS (Spam and Open-Relay Blocking System): Not Found
SURBL: Not Found

The IP address is well in all tests. The PTR record points to my isp anyway the problem is why an incomplete ip address appear in my mail logs in the followin form XX.XXX. look, only the first and second octets.

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