Re: SMTP no-such-user issues
Steve Bertrand wrote: Hi everyone, We are experiencing an issue in regards to SMTP MTA relay responses regarding 'no such user', and it *apparently* appears to be only occurring when a particular site attempts to deliver email to us. For the sake of completeness... The problem has been found within the defining of a variable in chkuser: But I found the problem. chkuser_settings.h shows: #define CHKUSER_NORCPT_STRING 511 sorry, no mailbox here by that name (#5.1.1 - chkuser)\r\n I changed the 511 to 550 (as shown here http://www.faqs.org/rfcs/rfc821.html ) I'm also told that version 2.09 of chkuser works around this problem. For those who have recommended Postfix, I'd love to switch, however Qmail is tied so tightly into my mail infrastructure at this point that I don't think it would be possible without months and months of planning, and redeveloping a whole lot of internal management software. Thanks everyone, Steve
Re: SMTP no-such-user issues
Steve Bertrand wrote: Hi everyone, We are experiencing an issue in regards to SMTP MTA relay responses regarding 'no such user', and it *apparently* appears to be only occurring when a particular site attempts to deliver email to us. Any advice on how to further troubleshoot my issue would be greatly appreciated. Because I have been inundated with off-list replies, I'll post my findings here. First, a screen cap of me composing a message, in which two of the addresses are easily identified as valid, and two are clearly not: http://ibctech.ca/nanog_smtp/hotmail_compose.jpg ...when I sent it, I received thus: http://ibctech.ca/nanog_smtp/hotmail_response.txt So, we'll try it from a different server: http://ibctech.ca/nanog_smtp/local_compose.jpg ...hmmm, I received the message at [EMAIL PROTECTED] (even though the To: field was cropped out of the jpg) this time, and my server generated the followingAFAICT, correct 551 error(s): http://ibctech.ca/nanog_smtp/local_err.txt I'm willing to provide any more documentation required in order to get this issue sorted. Thank you everyone, I truly appreciate it. Steve
RE: SMTP no-such-user issues
Once you've performed a full capture on port 25, Wireshark does a nice job of providing an option to extract the relevant conversation by right-clicking on just one packet in that conversation and choosing something called Follow the TCP stream, I believe. Frank -Original Message- From: Steve Bertrand [mailto:[EMAIL PROTECTED] Sent: Tuesday, June 17, 2008 7:44 AM To: [EMAIL PROTECTED] Cc: nanog@nanog.org Subject: Re: SMTP no-such-user issues Frank Bulk - iNAME wrote: Please share a packet capture of a working and not working SMTP exchange. In order to provide the highest amount of clarity, could you recommend a specific set of tcpdump command line args that I should use? Steve
Re: SMTP no-such-user issues
Frank Bulk - iNAME wrote: Once you've performed a full capture on port 25, Wireshark does a nice job of providing an option to extract the relevant conversation by right-clicking on just one packet in that conversation and choosing something called Follow the TCP stream, I believe. Ok. I've never captured in tcpdump and then imported into Wireshark before, but I'll do some tests, scp the file to my Windows workstation, then follow the stream. Once I ensure I get a clean stream, I'll post the results. Steve
Re: SMTP no-such-user issues
On 18/06/2008, at 1:20 AM, Steve Bertrand wrote: Steve Bertrand wrote: Frank Bulk - iNAME wrote: Once you've performed a full capture on port 25, Wireshark does a nice job of providing an option to extract the relevant conversation by right-clicking on just one packet in that conversation and choosing something called Follow the TCP stream, I believe. Ok. I've never captured in tcpdump and then imported into Wireshark before, but I'll do some tests, scp the file to my Windows workstation, then follow the stream. Once I ensure I get a clean stream, I'll post the results. As I research the documentation on the how-to specifics on capturing with tcpdump in a format that is Wireshark compatible, is there anyone here that could perform a simple test against their own domain email system, that can confirm or deny what I have been witnessing? Wireshark reads pcap files. Spit them out with this option on the tcpdump commandline. -w file -- Nathan Ward
Re: SMTP no-such-user issues
Shane Short wrote: are you using vpopmail with your qmail install? (I can't seem to load your errors again, I recall they were chkuser failures) Yes, vpopmail against MySQL. I've had this problem before when I've run out of MySQL connections and vchkuser was then failing. Thanks for the feedback, but this is not the case. The problem has been identified to be extraordinarily site specific. I'm attempting to follow the recommendations of members that mailed me off list one at a time, and am proceeding with testing. It would be of great value if other mail admins who are running Qmail that have a few minutes could contact me off list in order to compare some quick test results/config setups. Steve
