letsencrypt could not start HTTP server for challenge: listen tcp :80: bind: address already in use

[sysdev]

@sec-is tool ss is provided by the iproute package. On RHEL 7 systems you should have iproute 4.11.0-30 installed.

The script is tested against this version and do handle --no-header parameter. Could you please provide the output of the following commands:

• yum info iproute should show Version : 4.11.0
• ss --version should print iproute2-ss170501

Quick search on the upstream repo shows this option was introduced in iproute 4.7.0:

ss: Add option to suppress header line · iproute2/iproute2@7a4559f

Add option to suppress header line. When used the following line is not shown: "State Recv-Q Send-Q Local Address:Port Peer Address:Port" Signed-off-by: David Ahern <dsa@cumulus...

github.com

At the time this feature was introduced internal iproute2 snapshot version was 160518

iproute2/include/SNAPSHOT.h at 7a4559f67c8c4dcd6d8d361018ac239090713b69 · iproute2/iproute2

Iproute2 Source Code Mirror - This is a publish-only repository. Please follow README.devel procedure for any changes. - iproute2/iproute2

github.com

Oh great!

I totally missed that. The specific server indeed had a yum cache error and didn't get updated.

Thanks for pointing it out to stupid me!