Package: exim4 Version: 4.92-8+deb10u6 I got bounces due to delivery failures when mailing someone from my exim4-based mail server. The log file contains:
2021-07-13 06:20:20.720 [13321] 1m1lRa-0002RD-DO H=mailcluster.loopia.se [2a02:250:0:48::13]:25: DANE error: tlsa lookup DEFER 2021-07-13 06:20:20.721 [13321] 1m1lRa-0002RD-DO H=mailcluster.loopia.se [2a02:250:0:48::12]:25: DANE error: tlsa lookup DEFER 2021-07-13 06:20:20.722 [13321] 1m1lRa-0002RD-DO H=mailcluster.loopia.se [2a02:250:0:48::11]:25: DANE error: tlsa lookup DEFER 2021-07-13 06:20:20.722 [13321] 1m1lRa-0002RD-DO H=mailcluster.loopia.se [2a02:250:0:48::14]:25: DANE error: tlsa lookup DEFER 2021-07-13 06:20:20.723 [13321] 1m1lRa-0002RD-DO H=mailcluster.loopia.se [93.188.3.11]:25: DANE error: tlsa lookup DEFER 2021-07-13 06:20:20.723 [13321] 1m1lRa-0002RD-DO H=mailcluster.loopia.se [93.188.3.12]:25: DANE error: tlsa lookup DEFER 2021-07-13 06:20:20.723 [13321] 1m1lRa-0002RD-DO H=mailcluster.loopia.se [93.188.3.13]:25: DANE error: tlsa lookup DEFER 2021-07-13 06:20:20.724 [13321] 1m1lRa-0002RD-DO H=mailcluster.loopia.se [93.188.3.14]:25: DANE error: tlsa lookup DEFER 2021-07-13 06:20:20.726 [13320] 1m1lRa-0002RD-DO == x...@vetiveradv.se R=dnslookup T=remote_smtp defer (-36): DANE error: tlsa lookup DEFER After a couple of days, it times out and I get a bounce back. Before I could try the 'hosts_try_dane' option, I changed the /etc/resolv.conf DNS servers from my ISP's to my own 127.0.0.1 unbound instance, thinking it may be a DNS server problem. Indeed, that resolved my problem, and delivery worked again. While the domain might contain buggy DANE records (it passes some checks [2] though?), it seems like a exim4 problem that things works fine with one DNS server and not another. I'm guessing the problem was not with the DANE records, but with the responses received from the DNS server? How can I debug the DNS problem further? This is the first case this happened, and I'm emailing many domains with DANE records, so I'm a bit puzzled what went wrong here. /Simon [1] https://lists.exim.org/lurker/message/20200325.171053.9794c778.en.html [2] https://dane.sys4.de/smtp/vetiveradv.se
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