How is hostname determined?

[CharlieD]

How is the hostname determined that we see in the network map and the traffic monitor? Here's why I ask.

My main Linux server (fedora 19) is connected to one of the wired ports and has a static IP address. The hostname is oak. Sometimes the network map would show this name and sometimes it only showed the MAC address.

Recently I installed the Plex Media Server (http://plex.tv). Now the hostname shows up as Plex Media Serv (yes, that's as long as it is). The hostname command on the server still returns the original hostame - oak - and /etc/hosts has not changed. So, where is the router getting the hostname from?

--Charlie

 

[thelonelycoder]

What comes out when you enter hostname in your Linux terminal?

# hostname

Hostname is stored in /etc/hostname
If you change it reboot and it will be active.

 

[CharlieD]

As I noted above, the hostname command still returns oak. /etc/hostname still has oak as does /etc/hosts.

 

[thelonelycoder]

Do you have apache or any other webserver running apart from Plesk?
Apache's ServerName directive might enforce it.

 

[RMerlin]

How is the hostname determined that we see in the network map and the traffic monitor? Here's why I ask.

My main Linux server (fedora 19) is connected to one of the wired ports and has a static IP address. The hostname is oak. Sometimes the network map would show this name and sometimes it only showed the MAC address.

Recently I installed the Plex Media Server (http://plex.tv). Now the hostname shows up as Plex Media Serv (yes, that's as long as it is). The hostname command on the server still returns the original hostame - oak - and /etc/hosts has not changed. So, where is the router getting the hostname from?

--Charlie

Here's the order used to determine a device's name on the Networkmap, with the highest priority at the top:

- If a name is defined on the DHCP reservation page, that name is used
- Otherwise, if the client provided its hostname while requesting a lease,
- Otherwise, if the device returns a name when doing a Netbios lookup (those usually show up in uppercase)

 

[CharlieD]

Here's the order used to determine a device's name on the Networkmap, with the highest priority at the top:

- If a name is defined on the DHCP reservation page, that name is used
- Otherwise, if the client provided its hostname while requesting a lease,
- Otherwise, if the device returns a name when doing a Netbios lookup (those usually show up in uppercase)

Server has a static IP address. No DHCP so the first two do not apply. Server is Linux. netbios is a Windows thing, right (sorry, I'm a Linux/UNIX admin in real life. Windows is not my forte.) However, it does run Samba but I have not touched that in ages. Actually. netbios name in smb.conf is commented out. I do run a web server. ServerName is www.dennett.org.

 

[john9527]

Even though I have specified the router to be the WINS server, the names don't show up until the client renews it's lease.

Back on my old router with Tomato firmware, I was able to work around this by adding dchp-host=<mac address>,<name> entries into the dnsmasq.config. I have this in place with a dnsmasq.conf.add, but it doesn't seem to work on this firmware.

 

[RMerlin]

Server has a static IP address. No DHCP so the first two do not apply. Server is Linux. netbios is a Windows thing, right (sorry, I'm a Linux/UNIX admin in real life. Windows is not my forte.) However, it does run Samba but I have not touched that in ages. Actually. netbios name in smb.conf is commented out. I do run a web server. ServerName is www.dennett.org.

Netbios also applies to Samba. Any SMB device will have a Netbios name associated to it.

Note that even if the server uses a static IP, a DHCP reservation the router with a matching MAC will still be used by Networkmap for name resolution.

 

[thelonelycoder]

I have this in place with a dnsmasq.conf.add, but it doesn't seem to work on this firmware.

I have just done a couple of tests. I use dnsmasq to resolve my internal testservers which I have given .dev and .test "TLDs" (CentOS Servers).
This works great with entries in /jffs/configs/dnsmasq.conf.add as follows:

address=/dev/<ip-address>
address=/test/<ip-address>

Now I can use domain.dev or anotherdomain.test and it will resolve to the correct Testserver.
However, if I ping 'dev' it will not resolve. They will, however resolve to <mycompanyname>.dev as that is their hostname. Thats not a problem for my environment but now I was curious as to why 'dev' is not resolved. I have changed the /dev/ part to the following and pinged:
ping dev --> no resolve as mentioned above
ping centos-dev --> no resolve
ping whatever.dev --> resolved, as expected

Conclusion is that address=/dev/<ip-address> is resolved as either a tld (dev) or a domain name (whatever.dev).
So you could name your devices with names separated by a . (dot) eg oak.lan or oak.local and you'd have a valid hostname for your LAN.

For CharlieD's www.dennett.org you could add address=/dennett.org/<ip-address> to resolve to your server internally. If you want to do so (I see your also into SETI. I cruch for SETI, LHC and others as well... since about 1999)

 

[RMerlin]

If Networkmap resolution is what you are after, then enter them on the DHCP reservation list. Even if your clients are using a static IP, it will still be used by Networkmap for name resolutions.