At home, I have an AVM FRITZ!Box router. That does some DNS magic and lets you resolve names in the local network. So I can do ssh martin-friese.fritz.box from another computer and get a connection to the laptop. This nicely works without any Avahi/Zeroconf/Bonjour stuff and therefore also supports Windows and Android right away. The address http://fritz.box gets resolved to the router's web interface (192.168.???.1).

At the university, my computer still has the hostname martin-friese.fritz.box. Perhaps this got baked into my Fedora installation a little too deep. I guess I should rather have martin-friese and let the FRITZ!Box DNS bake in the .fritz.box when I am at home.

When I now try to resolve a non-existing hostname, I get this:

$ host this-does-not-exist
this-does-not-exist.fritz.box has address 127.0.53.53                                                                  
this-does-not-exist.fritz.box mail is handled by 10 your-dns-needs-immediate-attention.box.

An internet search on your-dns-needs-immediate-attention tells me that the .box TLD is now a valid domain and that therefore there is a clash of my DNS with the global DNS.

The output of dig does not really help me.

$ dig this-does-not-exist
                                                                                                                       
; <<>> DiG 9.10.4-P5-RedHat-9.10.4-4.P5.fc25 <<>> this-does-not-exist                                                  
;; global options: +cmd                                                                                                
;; Got answer:                                                                                                         
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 10457                                                             
;; flags: qr rd ra ad; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1                                                
                                                                                                                       
;; OPT PSEUDOSECTION:                                                                                                  
; EDNS: version: 0, flags:; udp: 4096                                                                                  
;; QUESTION SECTION:                                                                                                   
;this-does-not-exist.           IN      A                                                                              
                                                                                                                       
;; AUTHORITY SECTION:                                                                                                  
.                       10800   IN      SOA     a.root-servers.net. nstld.verisign-grs.com. 2017013000 1800 900 604800 86400
                                                                                                                       
;; Query time: 13 msec                                                                                                 
;; SERVER: 131.220.226.3#53(131.220.226.3)                                                                             
;; WHEN: Mo Jan 30 16:51:54 CET 2017                                                                                   
;; MSG SIZE  rcvd: 123

So I guess I just need to change my hostname to martin-friese without the .fritz.box? Or should I change it to friese.martin-ueding.de, I own the domain but the registrar does not know anything about my laptop.

StrictHostKeyChecking no

host juqueen
hostname juqueen.fz-juelich.de
user hbn28e
controlpath ~/.ssh/controlmasters/%r@%h:%p
controlmaster auto
controlpersist 15m


host judac
hostname judac.fz-juelich.de
user hbn28e
controlpath ~/.ssh/controlmasters/%r@%h:%p
controlmaster auto
controlpersist 15m

host martin-ueding.de
hostname martin-ueding.de
user ssh-444717-mu
StrictHostKeyChecking yes

host hiskp
hostname plato.itkp.uni-bonn.de                                                                                        
user ueding                                                                                                            
                                                                                                                       
host chaos                                                                                                             
hostname chaos.stw-bonn.de                                                                                             
user mu                                                                                                                
                                                                                                                       
host gateway.cb.uni-bonn.de                                                                                            
ForwardAgent yes                                                                                                       
hostname gateway.cb.uni-bonn.de                                                                                        
user ueding                                                                                                            
checkhostip yes                                                                                                        
controlpath ~/.ssh/controlmasters/%r@%h:%p                                                                             
controlmaster auto                                                                                                     
controlpersist 15m                                                                                                     
                                                                                                                       
host qbig                                                                                                              
ForwardAgent yes                                                                                                       
#hostname gateway.cb.uni-bonn.de                                                                                       
ProxyCommand ssh gateway.cb.uni-bonn.de "nc qbig %p"                                                                   
user ueding                                                                                                            
checkhostip yes                                                                                                        
controlpath ~/.ssh/controlmasters/%r@%h:%p                                                                             
controlmaster auto                                                                                                     
controlpersist 15m                                                                                                     
                                                                                                                       
host gsp.fz-juelich.de                                                                                                 
hostname gsp.fz-juelich.de                                                                                             
identityfile ~/.ssh/id_gsp_owncloud                                                                                    
                                                                                                                       
host martin-welsh                                                                                                      
hostname martin-welsh.fritz.box                                                                                        
                                                                                                                       
host martin-shire                                                                                                      
hostname martin-shire.fritz.box                                                                                        

host martin-friese
hostname martin-friese.fritz.box
#hostname 192.168.188.71

host root@martin-welsh
user root
hostname martin-welsh.local

host martin-criollo
hostname 192.168.188.21
user shell
port 2222

host martin-falabella
hostname martin-falabella.fritz.box
port 2222

host cip
hostname cip-pool.physik.uni-bonn.de
user s6mauedi

I have a Fedora 25 machine. Sometimes I misspell a hostname for SSH. Then I do ssh examle.com. For some reason, I then get connected to my machine (localhost) via SSH. I notice this because if there are SSH_ variables in the environment, my shell prompt shows that.

Right now at home, I get a clean hostname resolve error. What could be the cause of this on occasion? Some local DNS just resolving everything it does not know to 127.0.0.1?

I have a Fedora 25 machine. Sometimes I misspell a hostname for SSH. Then I do ssh examle.com. For some reason, I then get connected to my machine (localhost) via SSH. I notice this because if there are SSH_ variables in the environment, my shell prompt shows that.

Right now at home, I get a clean hostname resolution error. What could be the cause of this on occasion? Some local DNS server just resolving everything it does not know to 127.0.0.1?