Phil Wieland wrote:

I attach two strace reports, strace-good shows a successful use, strace-bad shows it failing after a reboot. In both cases I just telnet

to localhost 55899, which gives the smtp server's banner in the good case.

I analyzed your dumps and I was able to diagnose your problem. Your stunnel.conf contains: chroot = /var/lib/stunnel4/ Unfortunately this directory does not contain resolver configuration files: [pid 1548] open("/etc/resolv.conf", O_RDONLY) = -1 ENOENT (No such file or directory) [pid 1548] uname({sys="Linux", node="friedbread.liverpub.com", ...}) = 0 [pid 1548] open("/etc/hosts", O_RDONLY|O_CLOEXEC) = -1 ENOENT (No such file or directory) [pid 1548] stat64("/etc/resolv.conf", 0xb74a424c) = -1 ENOENT (No such file or directory) As the result resolver tries to send its packets to INADDR_ANY: [pid 1548] socket(PF_INET, SOCK_DGRAM|SOCK_NONBLOCK, IPPROTO_IP) = 13 [pid 1548] connect(13, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("0.0.0.0")}, 16) = 0 which of course fails: [pid 1548] send(13, "\257\271\1\0\0\1\0\0\0\0\0\0\4smtp\nblueyonder\2co\2"..., 39, MSG_NOSIGNAL) = 39 [pid 1548] poll([{fd=13, events=POLLIN}], 1, 5000) = 1 ([{fd=13, revents=POLLERR}])

These are WITHOUT the suggested patch, I am not really equipped for building on this server.

The patch should solve your problem by causing stunnel to wait until your resolver is available before chroot(2) is executed. Workarounds: 1. mkdir /var/lib/stunnel4/etc && cp /etc/resolv.conf /var/lib/stunnel4/etc/ 2. Use IP address instead of host names in your stunnel.conf 3. Add static IP address of your remote host to /etc/hosts Best regards, Mike