From: zsd@jdvb.ca   
      
   On 2025-12-25 at 19:37 AST, Sylvain Robitaille  wrote:   
   > On 2025-12-25, Jim Diamond wrote:   
   >   
   >> Here is the message in maillog when it tried to send an email while the   
   >> network was down:   
   >>   
   >> ------------------   
   >> ...   
   >> Dec 16 15:05:58 x360 postfix/smtp[2479]: AA6B21E0B4C: to=, relay=none, delay=0.05, delays=0.03/0.01/0/0, dsn=4.4.3,   
   status=deferred (Host or domain name not found. Name service error for   
   name=MY_SMTP_SERVER type=A: Host not found,    
   try again)   
   >> ------------------   
   >   
   > Ok, that's not surprising ...   
   >   
   >> Once the network was back, I tried running the queue:   
   >>   
   >> ------------------   
   >> ...   
   >> Dec 16 15:06:17 x360 postfix/smtp[2479]: AA6B21E0B4C: to=, relay=none, delay=19, delays=19/0/0/0, dsn=4.4.3,   
   status=deferred (Host or domain name not found. Name service error for   
   name=MY_SMTP_SERVER type=A: Host not found, try    
   again)   
   >> ------------------   
   >   
   > But this is ...   
      
   Yeah, surprises me too.   
      
   > Here's a thought ... It won't help solve the problem but it might   
   > help identify the cause ...   
   >   
   > Perhaps just before and just after running "sendmail -v -q" try running   
   > "getent hosts MY_SMTP_SERVER" (with the correct hostname, of course)   
   > and confirm that the system is generally able to resolve the hostname?   
      
   > Based on the timestamps from your log extracts above, I'm guessing   
   > (and yes, only guessing) that the attempt to flush the mail queue   
   > is happening before the resolver is able to fulfill its role.   
   > My suggestion here might help confirm or disprove that.  I hope that   
   > it helps.   
      
   Thanks for the idea.  I will give it a try the next time I do this to   
   myself.  (I have long since cleaned /var/spool and resent the message.)   
      
   In the above case, unless my memory completely fails me, the network was up   
   and running properly (although that does not preclude the possibility that   
   there was some issue looking up my particular mail server).  Having said   
   that, in past cases I tried to encourage postfix by sending other emails   
   while the stuck one was in the queue, and those emails went happily on   
   their way.  Which makes me think that postfix is doing something weird with   
   mail messages that have already failed, as opposed to having issues finding   
   the server.   
      
   Having said that, not having perused the postfix code, I will admit to   
   having little idea of what is going on inside.   
      
   Cheers.   
                                      Jim   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)