Error 451 - Could not complete sender verify (in reply to RCPT TO command)
ijez
I'm a newbie postfix and still learning it. Currently, the postfix server had run on my productions for about 4-5 month without any problem until lately i got lot of complaint from my staff that her mail keep bounce back to her with the error like below :
......................................................
The Postfix program
<g.j.w...@apu.ac.uk>: host mail-filter.apu.ac.uk[193.63.55.15] said:
451-host lookup did not complete 451 Could not complete sender verify
(in reply to RCPT TO command)
.......................................................
I have search the google for the error messages without any luck or maybe i'm search for a wrong phase, so, can someone on this list please bright me what was wrong here? or did i need to do any extra configurations?
Please help me and if you need any configurations or more server info, then feel free to ask since i don't know which is relavent with this error messages.
Thanks In Advances and sorry for my bad english.
Thanks and Regards,
ijez
Andreas Winkelmann
> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
> <html>
> </html>
Please send your Mail again, but next time without HTML.
--
Andreas
Andreas Winkelmann
Please don't Hijack Threads. Create a new Message not Reply old ones and
change the Subject. Yes we see that...
> I'm a newbie postfix and still learning it. Currently, the postfix server
> had run on my productions for about 4-5 month without any problem until
> lately i got lot of complaint from my staff that her mail keep bounce back
> to her with the error like below :
> ......................................................
> The Postfix program
>
> <g.j.w...@apu.ac.uk>: host mail-filter.apu.ac.uk[193.63.55.15] said:
> 451-host lookup did not complete 451 Could not complete sender verify
> (in reply to RCPT TO command)
> .......................................................
This is a Message about a tempary Error from the Host "mail-filter.apu.ac.uk".
Seems like some DNS Stuff, or maybe the Host tries to send a Mail back to
your host while your session and failed. But at least you should ask the
Admin from "mail-filter.apu.ac.uk".
> I have search the google for the error messages without any luck or maybe
> i'm search for a wrong phase, so, can someone on this list please bright me
> what was wrong here? or did i need to do any extra configurations?
>
> Please help me and if you need any configurations or more server info, then
> feel free to ask since i don't know which is relavent with this error
> messages.
--
Andreas
ijez
>
> Please don't Hijack Threads. Create a new Message not Reply old ones and
> change the Subject. Yes we see that...
>
Ops, i have been cought, sorry for that.. lesson learn
>
> This is a Message about a tempary Error from the Host "mail-filter.apu.ac.uk".
> Seems like some DNS Stuff, or maybe the Host tries to send a Mail back to
> your host while your session and failed. But at least you should ask the
> Admin from "mail-filter.apu.ac.uk".
>
The problem is, I can't reach any user at domain apu.ac.uk to inform the problem, all the email to that domain will bounce back with that error messages.
Anyway thanks for the response, really appreciate it.
Thanks and regards,
ijez
ijez
>
> This is a Message about a tempary Error from the Host "mail-filter.apu.ac.uk".
>
In this case, does the email will be deliver to the sender or it's will completely discard?
Thanks In Advances
Regards,
ijez
Andreas Winkelmann
> > This is a Message about a tempary Error from the Host
> > "mail-filter.apu.ac.uk". Seems like some DNS Stuff, or maybe the Host
> > tries to send a Mail back to your host while your session and failed. But
> > at least you should ask the Admin from "mail-filter.apu.ac.uk".
>
> The problem is, I can't reach any user at domain apu.ac.uk to inform the
> problem, all the email to that domain will bounce back with that error
> messages.
Maybe you can check your Log for the Time you try to send a Mail to that
Domain if the Server tries to connect to you and fails.
And check your DNS-Records for your Domain and your Mailserver.
--
Andreas
Andreas Winkelmann
> > This is a Message about a tempary Error from the Host
> > "mail-filter.apu.ac.uk".
>
> In this case, does the email will be deliver to the sender or it's will
> completely discard?
The Server rejects the Mail with a 4xx Error. This is temporary and your
Mailserver should try it again to deliver the Mail. Look in your Queue
(mailq).
--
Andreas
ijez
>
> Maybe you can check your Log for the Time you try to send a Mail to that
> Domain if the Server tries to connect to you and fails.
>
> And check your DNS-Records for your Domain and your Mailserver.
>
> --
> Andreas
This is really weird, I'm suspecting the problems with the dns. Sorry if this was OT but, I need to conform this, can anyone on the list dig into mail.ipg.edu.my or mail.kutpm.edu.my? It's get the answer if I ask my friend at branches site to do a nslookup and dig but if I try online nslookup or dig, I don't get any answer from the dns server.
Thanks and regards,
zamri
Andreas Winkelmann
> This is really weird, I'm suspecting the problems with the dns. Sorry if
> this was OT but, I need to conform this, can anyone on the list dig into
> mail.ipg.edu.my or mail.kutpm.edu.my? It's get the answer if I ask my
> friend at branches site to do a nslookup and dig but if I try online
> nslookup or dig, I don't get any answer from the dns server.
There are some sites in the Internet where you can do DNS-Queries from. One
for example is www.dnsstuff.com.
--
Andreas
Sandy Drobic
That is exactly the problem. The nameserver cannot be queried from outside.
http://www.dnsreport.com/tools/dnsreport.ch?domain=kutpm.edu.my
Sandy
ijez
>
> There are some sites in the Internet where you can do DNS-Queries from. One
> for example is www.dnsstuff.com.
>
> --
> Andreas
Thanks for the link, I have check it and it seem that the domain was not resolve when I use dnslookup. It's really weird because I ask my collages at different state in my country to check the domain and it's was resolve perfectly. Need to check with my ISP.
Anyway, thank for the great help. Really appreciated it :)
Thanks and regards,
ijez
ijez
>
> That is exactly the problem. The nameserver cannot be queried from outside.
>
> http://www.dnsreport.com/tools/dnsreport.ch?domain=kutpm.edu.my
>
> Sandy
Yeah, this one is pretty weird.. My collages said it was solve perfectly ( that why he/she can send email and browse the web for that domain ) in different state in my country but it's wasn't resolve from outside of my county. It's possible for the ISP to block any DNS request from outside? Need to check with them.
Anyway, thank for your help.
Thanks and regards,
ijez
Keith Matthews
"ijez" <ije...@gmail.com> wrote:
> Hi,
>
> >
> > That is exactly the problem. The nameserver cannot be queried from
> > outside.
> >
> > http://www.dnsreport.com/tools/dnsreport.ch?domain=kutpm.edu.my
> >
> > Sandy
>
> Yeah, this one is pretty weird.. My collages said it was solve
> perfectly ( that why he/she can send email and browse the web for that
> domain ) in different state in my country but it's wasn't resolve from
> outside of my county. It's possible for the ISP to block any DNS
> request from outside? Need to check with them.
>
If your ISP is indeed blocking DNS requests from outside then they are
incompetant and/or deliberately abusive of established internet
procedures.
Move to a different ISP if you can.
--
Due to excessive spam as a result of archiving of this list I only
accept mail through the list server.
ijez
>
> If your ISP is indeed blocking DNS requests from outside then they are
> incompetant and/or deliberately abusive of established internet
> procedures.
>
> Move to a different ISP if you can.
>
> --
> Due to excessive spam as a result of archiving of this list I only
> accept mail through the list server.
I'm now in the mid of troubleshooting this problem with my ISP and yes, I will do forward the report to the management and advice them to changing the ISP.
Thanks for the advice and handful help :)
Regards,
ijez