Can't access server via hostname

[zigmo]

I setup a 9.10 server with a static IP address for a DAViCal project on my office network. I can access the server via SSH using it's IP address, but when I try via it's hostname, I get:


Could not resolve hostname [server's hostname]: Name or service not known.

Any suggestions as to where to look to resolve this would be appreciated.

[almostalive2009]

if you edit /etc/hosts and add an ip address and a host name it will tell the computer where to go when you use that host name. sorry if this isnt the answer your looking for

[sanderj]

From Ubuntu to Ubuntu? If so, you can ssh to <hostname>.local.

So, something like "ssh superbox2.local. "

No DNS nor host file needed, just Bonjour/Zeroconf (which is in Ubuntu 9.10).

[zigmo]

I'm still pretty new to this, so all suggestions are helpful.
I'm using a linux workstation to access the linux server, so I'll try editing the hosts file for my own use and convenience.
The server is on my work network and the hostname shows up as ubuntu-server.[domainname].local - that's what I tried to SSH to. I'll try ubuntu-server.local and see if that works any better.
The big problem is that everyone else who will need to access this server will be on Windows or Mac systems. I'm not familiar with Bonjour/Zeroconf. Will it broadcast the server's hostname with it's IP address so other computers can access it with just the hostname?

[sanderj]

Yes, it will broacast the name. Don't forget the dot at the end.

Macs also speak Bonjour/Zeroconf. For Windows, you need to install it.

[zigmo]

Editing the hosts file worked like a charm ... for me. I've still got the other computers to consider.
I tried accessing from my ubuntu desktop via ubuntu-server.local (before editing the hosts file) and it didn't work. I've got the libnss-mdns package installed - do I need anything else?
I browsed on my mac and yep - there it was, so I guess bonjour/zeroconf broadcast is working.
This is my office network and I have access to our DNS. Can I make any changes there?

[sanderj]

I tried accessing from my ubuntu desktop via ubuntu-server.local (before editing the hosts file) and it didn't work. I've got the libnss-mdns package installed - do I need anything else?

I browsed on my mac and yep - there it was, so I guess bonjour/zeroconf broadcast is working.


What is the name of the ubuntu server? Is it "ubuntu-server"? Check with "uname -n". Use that name (followed by '.local.' ) to ping to.

Which Ubuntu version is running on the ubuntu server.


One-liner of the day below:



sander@quirinius:~$ ping `uname -n`.local.

PING quirinius.local. (192.168.2.163) 56(84) bytes of data.
64 bytes from quirinius.lan (192.168.2.163): icmp_seq=1 ttl=64 time=0.082 ms
64 bytes from quirinius.lan (192.168.2.163): icmp_seq=2 ttl=64 time=0.085 ms
^C
--- quirinius.local. ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1001ms
rtt min/avg/max/mdev = 0.082/0.083/0.085/0.009 ms
sander@quirinius:~$

[zigmo]

It's 9.10 and named "ubuntu-server." It was my first one and I wasn't feeling very creative. I verified the name with uname -n and the version with lsb_release -a.

When I ping, I get

ian@ubuntu-server:~$ ping `uname -n`.local
ping: unknown host ubuntu-server.local

I tried some tests from my desktop and got weird results (as you can see, I'm not very creative with machine names - I also redacted our domain name)


ian@ubuntu-desktop:~$ uname -n
ubuntu-desktop
ian@ubuntu-desktop:~$ ping `uname -n`.local
PING ubuntu-desktop.local (192.168.59.171) 56(84) bytes of data.
64 bytes from npi0e8456 (192.168.59.171): icmp_seq=1 ttl=64 time=0.079 ms
64 bytes from ubuntu-desktop.[domainname].local (192.168.59.171): icmp_seq=2 ttl=64 time=0.074 ms
64 bytes from npi0e8456 (192.168.59.171): icmp_seq=3 ttl=64 time=0.082 ms
64 bytes from ubuntu-desktop.[domainname].local (192.168.59.171): icmp_seq=4 ttl=64 time=0.085 ms
64 bytes from npi0e8456 (192.168.59.171): icmp_seq=5 ttl=64 time=0.083 ms
^C

Based on that, I tried:



ian@ubuntu-desktop:~$ ping ubuntu-server.[domainname].local
ping: unknown host ubuntu-server.pier59studios.local

I did verify that I can ping from the server to the desktop, but it only works when I ping ubuntu-desktop.[domainname].local

[sanderj]

On the machine not seeing bonjour/zeroconf, check /etc/nsswitch.conf; it should contain the mdns4 settings below:



sander@quirinius:~$ grep hosts /etc/nsswitch.conf
hosts: files mdns4_minimal [NOTFOUND=return] dns mdns4
sander@quirinius:~$

[zigmo]

I wasn't sure what you meant by "not seeing bonjour/zeroconf."
Is the desktop not seeing it because it can't ping the server or is the server not seeing it because it can't be pinged by the desktop? In either case, I sent the info from both machines:


ian@ubuntu-server:~$ grep hosts /etc/nsswitch.conf
hosts: files dns

ian@ubuntu-desktop:~$ grep hosts /etc/nsswitch.conf
hosts: files mdns4_minimal [NOTFOUND=return] dns mdns4

Does this mean that the desktop can be found via zeroconf (thus the server being able to ping it)

[sanderj]

On both machines, what's the output of


ps -ef | grep -i avahi

Here's mine:


sander@quirinius:~$ ps -ef | grep -i avahi
avahi 949 1 0 17:47 ? 00:00:00 avahi-daemon: running [quirinius.local]
avahi 950 949 0 17:47 ? 00:00:00 avahi-daemon: chroot helper
sander 4112 2656 0 20:09 pts/1 00:00:00 grep --color=auto -i avahi
sander@quirinius:~$

[zigmo]

Here you go:


ian@ubuntu-server:~$ ps -ef | grep -i avahi
ian 6550 5508 0 14:15 pts/0 00:00:00 grep --color=auto -i avahi

ian@ubuntu-desktop:~$ ps -ef | grep -i avahi
avahi 771 1 0 09:20 ? 00:00:02 avahi-daemon: running [ubuntu-desktop.local]
avahi 772 771 0 09:20 ? 00:00:00 avahi-daemon: chroot helper
ian 2389 2189 0 14:17 pts/2 00:00:00 grep -i avahi

So, if I understand this correctly, the desktop is using bonjour/zeroconf (since the avahi-daemon is running) so the server can find it, but the server isn't running it, so the desktop can't find it - right?

[sanderj]

Yes, combined with the nsswitch which instructs to use mdns = zeroconf = bonjour = avahi for lookups.

So, install avahi (or avahi-daemon, I don't know). Afterward check that /etc/nsswitch.conf is OK.

[sanderj]

PS from https://help.ubuntu.com/community/HowToZeroconf


Ubuntu 9.04 (Jaunty Jackalope)

Zeroconf is installed and configured by default in the Desktop version of Ubuntu 9.04.

<snip>

Ubuntu 7.04

Just install the package avahi-daemon to allow other hosts to see this host as hostname.local. (note the trailing dot).

HTH

[zigmo]

Thanks for all the great help - it worked like a charm, plus I learned a lot about zeroconf.

[sanderj]

To let Windows machines join in this bonjour / zeroconf happiness, you need to install Bonjour for Windows: http://support.apple.com/downloads/Bonjour_for_Windows

On Ubuntu, you can use avahi-discover to discover bonjour / zeroconf service on your network.

There is also a great Firefox Bonjour plugin bonjourfoxy, but alas the developer has stopped support for Firefox on Linux; it's now Mac and Windows only.

[zigmo]

Thanks for the extra info. It looks like everything can see everything now, but I'm having Apache problems now - I'm only seeing the default page and not the DAViCal setups ... but that's a question for another thread!