On Sun 10 Jul 2022, at 18:28, Greg Wooledge <g...@wooledge.org> wrote:
> Mine contains these lines: > > unicorn:~$ grep ::1 /etc/hosts > ::1 localhost ip6-localhost ip6-loopback > ff02::1 ip6-allnodes > > They were put there by Debian. I didn't touch them. [I got the ::1 and localhost the wrong way around in my earlier reply.] $ sudo fuser 25/tcp 25/tcp: 3778 $ ps -p 3778 -o comm= exim4 $ cat /etc/hosts 127.0.0.1 localhost 127.0.0.1 hostname ::1 localhost ip6-localhost ip6-loopback ff02::1 ip6-allnodes ff02::2 ip6-allrouters $ telnet localhost 25 Trying ::1... Connected to localhost. $ sudo ss -lnt | grep :25 LISTEN 0 20 127.0.0.1:25 0.0.0.0:* LISTEN 0 20 [::1]:25 [::]:* $ sudo reboot - set boot arg ipv6.disable=1 - NB ipv6 addresses still in /etc/hosts $ telnet localhost 25 Trying 127.0.0.1... Trying ::1... telnet: Unable to connect to remote host: Address family not supported by protocol ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ $ sudo ss -lnt | grep :25 $ Just out of interest: Now, comment out ipv6 in /etc/hosts $ cat /etc/hosts 127.0.0.1 localhost 127.0.0.1 hostname #::1 localhost ip6-localhost ip6-loopback #ff02::1 ip6-allnodes #ff02::2 ip6-allrouters $ sudo reboot - set boot arg ipv6.disable=1 $ telnet localhost 25 Trying 127.0.0.1... telnet: Unable to connect to remote host: Connection refused ^^^^^^^^^^^^^^^^^^ ??? $ sudo nft list ruleset $ $ ss -lnt | grep :25 $ $ ps -aux | grep exim gives only "grep exim" - exim4 is not running Does exim4 require ipv6? I can't find any obvious such config with sudo grep -Ri ipv6 /etc/exim4 sudo grep -Ri ip6 /etc/exim4 etc. etc. In Roger's case, telnet seems to be outputting the same error as exim4 is panic logging, which occurs when ipv6 is disabled and "::1 ..." exists in /etc/hosts. Coincidence? "When certain serious errors occur, Exim writes entries to its panic log. If the error is sufficiently disastrous, Exim bombs out afterwards" https://www.exim.org/exim-html-current/doc/html/spec_html/ch-log_files.html This suggests exim4 may not be listening having written to the panic log even if my ipv6 requirement is the result of some oddity. Again: On Sun 10 Jul 2022, at 15:38, Roger Price <deb...@rogerprice.org> wrote: > I removed the ipv6.disable=1 and rebooted, but this made no difference. IIUC, without a $ sudo update-grub before reboot, ipv6 is still disabled, assuming Roger described exactly what he did there. Does this seem a reasonable assessment? Best wishes, Gareth