Setting up NFS permissions on Synology for Linux (KDE Neon) - linux

I've followed the instructions on the this Synology article to set up NFS access between my Synology NAS and my Linux (KDE Neon) machine.
If I set the hostname to my local IP it works fine... but the trouble is my local IP changes so I'd need to keep updating the NAS permission settings.
If I use my hostname, let's call it my-linux-machine I get the following error:
mount.nfs: access denied by server while mounting 192.168.1.11:/volume1/Video
Synology support have advised that:
I've checked the log, and found you've tried to set the client Host name: my-linux-machine as you've mentioned.
For your information, this Host name should be a validate Domain name which can be resolved by your NAS's DNS server.
Thus, you'll need to apply a domain name for your Linux (KDE Neon) machine, and a server name is not able to use directly here.
To verify the domain name, you can check it by "Ping" command to your Linux server from your NAS server.
You may specify a host in three ways:
Single host
Wildcards: *, *.synology.com
Network segment: 203.74.205.32/255.255.255.0, 203.74.205.32/24
Here's where I'm stuck.
Could someone help me understand which of those three options are best suited to my needs?
Single host: sounds like the single IP method, or a FQDN which I'm unsure as to what my 'domain' would be if none of it needs to talk to the world wide web.
Wilcards: also mentions domain names... again, my setup doesn't need to leave my home network.
Network segment: could maybe work? But I'm unsure how to figure what my segment would be.
Thanks in advance!

In principle, you should be able configure the IP using a mask (based on the answer on the Synology forum):
192.168.1.0/255.255.255.0
Hope this helps!

Related

getting hostname of remote computers on the local network not setup in /etc/hosts

I have a new learning, I was trying to get hostname using python's socket.
so from my macbook I ran the below code:
socket.gethostbyaddr("192.168.1.111")
and I get the ('rock64', [], ['192.168.1.111']) then I tried IP address of a computer that is not on the network anymore but used to be:
socket.gethostbyaddr("192.168.1.189")
and it returned: ('mint', [], ['192.168.1.189']) then I realised its coming from the /etc/hosts file.
now in that host file I also have this entry:
/etc/hosts
172.217.25.3 google.com.hk
but if I try to get host from ip of wan address i get different results than expected!
socket.gethostbyaddr("172.217.25.3")
that returns ('hkg07s24-in-f3.1e100.net', ['3.25.217.172.in-addr.arpa'], ['172.217.25.3'])
so I am not wondering where in the later case of WAN ip address I am getting the hostname and why in case of local computer IP's I am getting hostname from the configured /etc/hosts file ?
How can we get hostname of host computers on the local network without socket.gethostbyaddr having to look into /etc/hosts file or by other means ?
This is opinion based answer to the question "how to build registry of network devices on your local network?"
The best way to build registry of devices on your local network is to setup ntopng on your gateway. It uses DPI (Deep Packet Inspection) Technics to collect information about hosts.
NTOPNG has nice user interface and displays host names (when possible).
You can assign aliases for specific hosts which do not leak host names via any protocol.
For some reasons ntopng developers did not include alias into json response for request http://YOUR-SERVER:3000/lua/host_get_json.lua?ifid=2&host=IP-OF-DEVICE .
You can add it manually by adding lines require "mac_utils" and hj["alias"]=getDeviceName(hj["mac_address"]) into file /usr/share/ntopng/scripts/lua/host_get_json.lua
You can use REST API to interrogate ntopng and use provided information for building any script you need.

Confluence in Docker can't see PostgreSQL in Docker

I'm trying to set up both Confluence and PostgreSQL in Docker. I've got them both up and running on my fully up to date CentOS 6 machine, with volume-mapping to the host file system so I can back them up easily. I can connect to PostgreSQL using pgAdmin from another machine just fine, and I can get into Confluence from a browser from that same machine. So, basically, both apps seem to be running as expected inside their respective containers and are accessible to the outside world, which of course eliminates a whole bunch of possibilities for my issue.
And that issue is that Confluence can't talk to PostgreSQL during initial setup, which is necessary for it to function. I'm getting connection failed errors (to be specific: "Can't reach database server or port : SQLState - 08001 org.postgresql.util.PSQLException: The connection attempt failed").
PostgreSQL is using the default 5432 port, which of course is exposed, otherwise I wouldn't be able to connect to it via pgAdmin, and of course I know the ID/password I'm trying is correct for the same reason (and besides, if it was an auth problem I wouldn't expect to see this error message). When I try to configure the database connection during Confluence's initial setup, I specify the IP address of the host machine, just like from pgAdmin on the other machine, but that doesn't work. I also tried some things that I basically knew wouldn't work (0.0.0.0, 127.0.0.1 and localhost).
I'm not sure what I need to do to make this work. Is there maybe some special method to specify the IP to a container from the same host machine, some nomenclature I'm not aware of?
At this point, I'm "okay" with Docker in terms of basic operations, but I'm far from an expert, so I'm a bit lost. I'm also not a big-time *nix user generally, though I can usually fumble my way through most things... but any hints would be greatly appreciated because I'm at a loss right now otherwise.
Thanks,
Frank
EDIT 1: As requested by someone below, here's my pg_hba.conf file, minus comments:
local all all trust
host all all 127.0.0.1/32 trust
host all all ::1/128 trust
local replication all trust
host replication all 127.0.0.1/32 trust
host replication all ::1/128 trust
host all all all md5
try changing the second line of the pg_hba.conf file to the following:
host all all 0.0.0.0/32 trust
this will cause PostgreSQL to start accepting calls from any source address. Since a docker container is technically not operating on localhost but on its own ip, the current configuration causes PostgreSQL to block any connections to it.
Also check if confluence is searching for the database on localhost. If that is the case change that to the ip of the hostmachine within the docker network.
Success! The solution was to create a custom network and then use the image name in the connection string to PostreSQL container from Confluence container. In other words, I ran this:
docker network create -d bridge docker-net
Then, on both of the docker run commands for the PostgreSQL and Confluence containers, I added:
--network=docker-net
That way, when I ran through the Confluence configuration wizard, when it asked for the hostname for the PostgreSQL server, I used postgres (the name I gave the container) rather than an IP address or actual hostname. Docker makes that work thanks to the custom network. This also leaves the containers available via the IP of the host machine, so for example I can still connect to PostgreSQL via 192.168.123.12:5432, and of course I can launch Confluence in the browser via 192.168.123.12:8080.
FYI, I didn't even have to alter the pg_hba.conf file, I just used the official PostgreSQL image (latest) as it was, which is ideal.
Thanks very much to RSloeserwij for the suggestions... while none of them proved to be the solution I needed, they did put me on the right track in the Docker docs, which, after some reading, led me to understand a few things I didn't before and figure out the config magic I needed.

Can't get DNSMASQ DHCP to configure multiple name servers

Perhaps someone has some help? I am running dnsmasq on Ubuntu 12.04 LTS. This server's address is 192.168.15.3. My gateway's DNS is 192.168.1.254, that takes me out to the Internet. I also have a special-purpose DNS at 192.168.15.2. So I wanted to give those 3 name servers to DHCP clients. This is my dnsmasq.conf server= section:
server=/localnet/192.168.15.3
server=/localnet/192.168.15.2
server=/15.168.192.in-addr.arpa/192.168.1.254
However, when I look at the DHCP allocation on a client, I see only 192.168.15.3 as the sole DNS server. Clients cannot access the Internet (the NIC on .3 is configured correctly and can access the Internet from its console login).
Granted, the first server= line is probably not necessary, but I added it thinking it may help, didn't.
What am I doing wrong? Thanks for your help!
OK, after MUCH experimentation, I found I had to push the option manually. In the dnsmasq.conf file, I added the following line:
dhcp-option=6,
like so:
dhcp-option=6,192.168.15.3,192.168.15.2,192.168.1.254
This served the correct list of name servers to DHCP clients.
The server lines are configuration for dnsmasq's own DNS server, about where it should forward DNS requersts that it receives in order to be able to resolve (and cache) them.
Only the dhcp-options are part of the DHCP configuration that get passed to DHCP clients - so, the accepted anser is correct, but I wanted to share why.

Getting Started with CouchDB

I've got CouchDB installed on my linux cloud server and I'm trying to access the "Futon Welcome Screen". The O'Reilly book says to go to "127.0.0.1:portnum", but I'm not working on localhost, it is my remote server, so I should be able to use "xxx.xxx.xxx.x:portnum" (my remote address) to access Futon right? This is not working, do I need a virtual host or something? Thanks.
Go to your local.ini file. (probably in /etc/couchdb) and set bind_address to either 0.0.0.0 (ie. respond to all IP addresses) or specify another IP address that you're either using in your LAN (private) or over the internet. (public)

xampp server (How to get up and running)

I've been developing locally on a little ubuntu netbook with xampp for about 7 months. Two weeks ago I got a computer I'd like to use as a server. I've installed the latest Ubuntu distribution and xampp, moved all my files over, and forwarded port 80. I've also got a domain name from dyndns.com which is being updated by a client which runs in my router (a Netgear WGR6154 v8).
Now, when I try to access my server by typing in the address I got from dyndns.com the browser loads until it timesout. I can access everything locally using localhost as the address so I believe xampp is running, just unable to connect with the internet.
In order to be able to view my files over the internet what should I do next?
Thanks to all in advance...
[I'm starting a bounty for the first person to help me get my files successfully online]
You have a combination of issues here, and that is something of a problem. Each issue is complex in an of itself. Here is what I would recommend to get you going for certain.
First verify that you can surf the web from your server. This will confirm that you have a working ethernet interface.
Step 1 make sure that XAMPP, and your files are viewable from your home network. I assume you are using something like 192.168.1.X for your network and perhaps your server is 192.168.1.10
Go to another computer in your house and type http://192.168.1.10/ and see if you can see your files. If you can then you know that the server is properly configured and XAMPP is working.
Then add an entry to your hosts file to resolve yourdnsrecord.com (or whatever your dyndns record is) to your private ip address. Then when you type yourdnsrecord.com into a browser from that computer you should still get your files. This will rule out your server being improperly configured to listen for that domain name.
Next you need to test to see if there is a firewall problem. To simplify this, first remove your home router from the equation. Instead, place your new server directly onto your internet connection. (assuming you can). This way, you do not need to have NAT or firewalls properly configured. Your dyndns name should map to a public IP and your server should then have that IP and be connected directly to the Internet. If you have your server directly connected, and the command ifconfig from the root prompt returns the same public IP address that your dynamic dns record is point to, then it should work.
It will make your life easier if you have an iphone or some other way to test how your network is seen from the Internet.
If your public IP as shown by ifconfig is different than the IP record in your dyndns account, then your dynamic dns update script is broken. manually set the IP, and see if things work.
It is very possible that this will not work. Some ISPs firewall port 80 preventing their subscribers from hosting servers. Once you have your server directly connected to the internet you can test this (even if your dns is not working) by using the public IP address. As root, type ifconfig from the command prompt to get your public ip address. Then type the command tcpdump -i eth? port 80 from the root prompt. eth? needs to be the same interface that you saw had a public IP address from the ifconfig command. usually this is eth0 but it might be wire0 or something like that.
This command will show you all traffic coming on port 80 to your server.
From an iphone (or whatever second Internet connection you have) browse to the IP address that you got from your ifconfig command. If you see something on your server (and it is directly connected to your ISP) then your ISP is not firewalling you.
If you can get to your server, when it is directly connected to the Internet, either by IP address or by DynDNS address, then your ISP is OK and it is time to debug your firewall.
Two things need to work for your firewall to be configured NAT, where the public address that your router gets from your ISP is converted into your private network and a firewall rule which permits that traffic. If you get this far, then you know your firewall is the problem and then it is just a matter of getting its configuration correct. There are far to many home routers to document here, but you usually can find how-to instructions for your router for this task from the manufacturers website (usually it is part of the manual)
If you follow these instructions exactly you will get your system working. Make comments on the process and I will be happy to modify this to make it clearer.
HTH,
-FT
You should make sure your xampp is not listening to only the localhost.
to do so edit your apache configuration file and check and search for Listen directive
you should be able to know also by analysing the output of netstat -a.
After that make sure your router is forwarding properly, using tcpdump would help.
drop me a comment if you need more help.
Cheers

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