Dont understand soem networking fundmentals need help

[Ambiguous-69]

Im not sure if i have set up my linux correctly with my adsl router so i need to know a few things.

Pretty much i want my adsl router to be the dhcp server and i assume from some articles i have read that it also has to be the dns.

What applications or daemons do i require for this?

How do i find out what my default gateway address is?

And is there anythinsg i have to disable that can conflict with teh router being dhcp?

[simonn]

If you are running dhcpd on your PC turn it off.

Turn on dhcp on your router.

Set up the network card on your PC to use DHCP.

"How do i find out what my default gateway address is?"

Your PC should get this when via dhcp.

[giulix]

Originally Posted by Ambiguous-69

How do i find out what my default gateway address is?

/sbin/ip route |grep default

[capnlinux]

In the configuration that you described, the default gateway address should be the address of the ADSL router. The local area network address, not the Internet address. Assuming that you know what that is or can look it up in the router configuration. It will probably be something like 192.168.0.1 if using a default configuration in the ADSL router.

[Ambiguous-69]

yeah i know how the dhcp works and dns, i just couldnt understand what you have to enable and what you dont, i tried to find info on it but i couldn't most examples or explanations where using a login program or setting the dhcp on the linux machine but i knew something was wrong as i couldnt get samba or cups or anything else working apart from the net when trying to connect to my other comp.

Im glad someone has cleared up the usage with teh dhcp for me. i posted a more detailed post before about what setup i wanted to use and what i wanted it to do but no one replied they just viewed it, since you seem to understand the fundementals of how linux works with hardware and software i will cut and paste what i wanted to achieve from a previous post, by the way how do i turn of the dhcp on linux, should i just stop teh daemon dhcp and also should i blank out the named servers in my resolve.conf files using teh # in front of the ip addresses.

[Ambiguous-69]

Im having soem problems networking with samba and i think it might be because i have setup my 2 linux machines incorrectly with my ADSL router, so here is the current setting so changes i have made.

I have 2 machines connecting to an adsl router, the router assigns ips to both machines acting as a dhcp which is the way i want it.

ive added the ethernet cards to both computers and have only added and changed these settings displayed. All other settings are on default or blank, mostly blank.

Computer 1
----------------
*Ethernet Card Settings*
- Automatically obtain ip address settings with dhcp
- Hostname (optional): = Hal9000 (realised this was required or else router will give both linux machines the same ip)
- Automatically obtain dns information from provider
- bind to mac address = contains mac address

*DNS settings*
- Hostname = Hal9000.MATRIX
- Primary DNS = contains ip address
- Secondary DNS = contains nothing
- Tertiary = contains nothing
- DNS search path = contains nothing

Computer 2
------------------
*Ethernet Card Settings*
- Automatically obtain ip address settings with dhcp
- Hostname (optional): = Mother
- Automatically obtain dns information from provider
- bind to mac address = contains mac address

*DNS settings*
- Hostname = Mother.MATRIX
- Primary DNS = contains nothing
- Secondary DNS = contains nothing
- Tertiary = contains nothing
- DNS search path = localdomain


What i dont understand is why the DNS settings are different on both computers ever since i changed the localhost.localdomain field to the ones i wanted.

Another thing i dont understand is why the DNS fields are different on both machines.

How do i tell linux that my ADSl router will be acting as the dhcp and that it is the gateway and that it will automatically dial in to my ISP.

accessing the internet from both computers is fine and my ADSL router dials in automatically but im sure i havn't set it up correctly when i see teh fields are different on both computers and when setting up sharing between the 2 linux machines with samba is failing.

any links to indepth documentation on how networking with an ADSL router in linux would be great oranyone who knows what pieces of information i have left out that may be making it difficult for me to get samba working correctly due to missing fields required in linux.

sorry if soem of it is repeated question but there was some thoer things i wasnt sure about and no one has replied so im hoping you guys would know"

[Ambiguous-69]

also another thing i wanted to add, do any of you guys know what a good GUI is for configuring iptables firewall and SEpolicies and other network settings , configurations. i saw in the other post that firewall builder is supposed to be good but im not sure if it is overkill or maybe not suited for the tasks of configuring all aspects of fc4 network configurations through teh use of a GUI

[capnlinux]

A few (maybe dumb) questions: Under bind to MAC address, you say = MAC address. Which MAC address is there? I cannot imagine the ADSL assigning the same IP address to both machines unless they had the same MAC address, but that just really wouldn't work at all so must not be the case.

Are you using a default iptables setup? If so SMB, the protocol used by Samba is blocked. You will need to allow it through the iptables firewall. If you've done all of the other Samba setup correctly this could be the only thing preventing it from working.

Not sure why the DHCP is giving different results on the two machines. I'm not at my Linux box right now so I can't check some of the setting right now.

[giulix]

You said you have 2 machines, but you didn't specify which operating system runs on each one: let's assume they both run Fedora. You also forgot to mention what kind of router you're dealing with, so let's assume your router is capable of acting as a dhcp server (otherwise it wouldn't be a router, right ?). There's no way your router can assign the same IP address to both machines unless it's broken. I suggest you start again from scratch: reconfigure your network devices and the router itself, until you have both FC systems set up right, each one with its own (different) IP address.
Check that by running /sbin/ifconfig on each one.
Then check that each machine has been configured to get DNS servers from the router. Both machines should present exactly the same content when you
cat /etc/resolv.conf
Finally, check that routing has been correclty configured on both machines with
/sbin/ip route |grep default

[Ambiguous-69]

yes they are both fedora core 4 machines, and im assuming that disabling the dhcprelay and dhcp daemon is what i would do to get both machines to look up the dhcp on the router. the bind to mac address was on by default but im not sure if i keep that setting on or off.

The dns ips in teh resolv.conf file are different on both machines, 1 machine shows to addresses and neither are the addresses of the router which im assuming it must be since the router would act as a the dns. the other machine simply has localhost in its resolv.conf file and nothing else.

Im not sure what settings have to be in what, only from what i have read on other sites. does the resolv.conf file contain teh ip addresses of teh dns servers and if so must it have teh address of my router since teh router is acting as a dns and downloading the addresses required of the real dns server at my ISP

[simonn]

Lets do things one step at a time. DHCP and DNS are different.

Turn dhcp and dhcp relay off on your PCs. For the sake of simplicity, you can only have one DHCP server ruuning on your network.

When a PC boots up, any network cards which are set to use DHCP will broadcast to the network, I want an IP address and all the network details. A DHCP server will be listening for this request and will send the PC all the information it asks for. So you need to the PC's network cards to use DHCP.

In Fedora Core 4 you can do this by using the Network option (sorry I do not have a access to my Fedora box at the mo - I am at work) which is under one of the sub menus of the Desktop menu. It should be easy to see how to do this. There will be options to pick up DNS servers and gateways etc from the DHCP server.

Once you have setup DHCP, reboot and make sure that the PC is picking up an ip address at boot time by using ifconfig in a terminal as root.

[Ambiguous-69]

Okay i have disabled both dhcp and dhcprelay daemons in services

get internet ip address dynamically from ISP is enabled on the router
get DNS address from isp is enabled on the router

on my ethernet device i have the following options

General
----------------
Activate device when computer starts - enabled
Allow all users to enable and disable the device - disabled
Enable IPv6 configuration for this device - disabled
Automatically obtain ip address settings with - dhcp
Hostaname (optonal) - Hal9000
Automatically obtain DNS information from provider - enabled

Route
-----------
Is empty

Hardware Device
----------------------------
Hardware - Curently the card i have added
Device alias number - disabled
Bind to mac address - enabled

[Ambiguous-69]

Results of ther commands you told me to type in and some information on router addresses
Router ip: 192.168.0.1
Hal9000:192.168.0.3

/sbin/ifconfig
eth0 Link encap:Ethernet HWaddr 00:10:B5:F8B:F8
inet addr:192.168.0.3 Bcast:192.168.0.255 Mask:255.255.255.0
inet6 addr: fe80::210:b5ff:fef8:dbf8/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:6835 errors:0 dropped:0 overruns:0 frame:0
TX packets:6598 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:3729356 (3.5 MiB) TX bytes:1011885 (988.1 KiB)
Interrupt:10 Base address:0xd800

lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:2332 errors:0 dropped:0 overruns:0 frame:0
TX packets:2332 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:2781268 (2.6 MiB) TX bytes:2781268 (2.6 MiB)

cat /etc/resolv.conf
; generated by /sbin/dhclient-script
nameserver 202.138.0.10
nameserver 202.138.0.11

/sbin/ip route |grep default
default via 192.168.0.1 dev eth0

[simonn]

What is not working now?

[Ambiguous-69]

well its not a matter of not working, i actually want you to give me feedback such as are those the right settings im using and the correct output there should be.

There is one thing im not to sure about, the named server output, shouldnt that be displaying the ip of my ADSL Router if i have enabled the option "Get DNS automatically from ISP" on my router