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I start by saying that my experience in networking is somewhere between low and medium.

I'm working on a Linux machine with DHCP configured and from tcpdump traces I see that the dhclient send the hostname "linux" in Option 12, Request packages. I verified the files /etc/hostname, /etc/hosts and /etc/dhclient.conf and there's no parameter related to the hostname that have the value "linux". I must specify that I use dhcpcd.

Any help/hint is appreciated since I don't have any ideas where that value is set.

23ars
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1 Answers1

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From man 5 dhclient.conf, the config entry is send host-name <...>. It's near the bottom. The example they give is:

interface "ep0" {
  send host-name "andare.example.com";
  request subnet-mask, broadcast-address, time-offset, routers,
    domain-name, domain-name-servers, host-name;
}

But, I doubt you need to put it under an interface section. I would not worry if it's sending Linux, just override it.

It may be being set via systemd. on openSUSE, the manpage for dhclient says it has a -H switch. YMMV.

Bib
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  • I checked the dhclient.conf and there's no send host-name. Only some send fqdn, but with the correct domain name. While in DHCP file from /etc/sysconfig/network there's DHCLIENT_HOSTNAME_OPTION="AUTO". – 23ars Mar 30 '22 at 08:38
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    It doesn't matter whether it's in dhclient.conf or not, just go by what the man page says. That `send fqdn` id for DDNS, again, look at the manpage. – Bib Mar 30 '22 at 08:43
  • Thankgs, I'll try! – 23ars Mar 30 '22 at 08:44