I've just had a very strange bug which cost me an hour to find. mailserver: postfix-2.5.1-28.5
On the mailserver, I should receive mail from 212.69.162.205. # dig -x 212.69.162.205 showed me a correct, existing PTR: 205.192-28.162.69.212.in-addr.arpa. 3600 IN PTR protegate5.zmi.at. Just the forward request doesn't fit the IP: # dig +short protegate5.zmi.at 212.69.164.56 and postfix refused to take the e-mail with this message: 450 4.7.1 Client host rejected: cannot find your hostname, [212.69.162.205] The log text is not correct, it should say "your PTR 212.69.162.205 doesn't fit the forward IP of protegate5.zmi.at". I changed the PTR to now be 205.192-28.162.69.212.in-addr.arpa. 3600 IN PTR protegate5old.zmi.at. and this fits the forward: # dig +short protegate5old.zmi.at 212.69.162.205 and then the e-mail passes through. I don't know if that has already been fixed, but it really should as the log messages suggests that we had a DNS issue while it really only was the misfit of forward/reverse lookups. I also looked at http://www.postfix.org/postconf.5.html#reject_unknown_client_hostname but found no mentioning of the message that's logged. But a "cannot find your hostname" is really not a good answer here. mfg zmi -- // Michael Monnerie, Ing.BSc ----- http://it-management.at // Tel: 0660 / 415 65 31 .network.your.ideas. // PGP Key: "curl -s http://zmi.at/zmi.asc | gpg --import" // Fingerprint: AC19 F9D5 36ED CD8A EF38 500E CE14 91F7 1C12 09B4 // Keyserver: wwwkeys.eu.pgp.net Key-ID: 1C1209B4
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