Weird Network Problem
 

I've been trying to fix this since late last week. I finally give up and decided to post in the hopes that one of you can see something I'm overlooking :)

Basically I'm setting up a small server at work, and it won't get any internet/network connectivity now. I should first explain my overall network topology to help clarify the problem. Please forgive the very lame picture.

http://personalwebs.oakland.edu/~ermcgrat/network.png

Now when I built/tested the slackware server box I placed it under the 24-port switch and just had it configure the network with DHCP. Everything worked fine so I know the NIC is ok. Moving the server to its new location (so as not to get traffic blocked by the firewall) and statically configuring the network I get nothing. However if I literraly unplug the cable from the slackware box and plug in a Windows machine and statically configure it with the same values it works fine.

I configured the network via netconfig. It is unable to ping the following with a host unreachable: google.com, google by ip, local ips.

Here is my /etc/rc.d/inet1.conf

IPADDR[0]="207.104.44.21"
NETMASK[0]="255.255.255.240"
USE_DHCP[0]="no"
DHCP_HOSTNAME=""
GATEWAY="67.124.9.185"
DEBUG_ETH_UP="no"

And my /etc/resolv.conf

nameserver 206.13.31.12

And here I believe is the problem
# route -n
Destination || Gateway || Mask | Flags| Metric | Ref | Use | Iface
207.104.44.16 || 0.0.0.0 || 255.255.255.240 | U | 0 | 0 | 0 | eth0
127.0.0.0 || 0.0.0.0 || 255.0.0.0 | U | 0 | 0 | 0 | lo

Why is the gateway showing as 0.0.0.0 when it specifically says in inet1.conf GATEWAY="67.124.9.185"? And why is it 207.104.44.16 when I set the ip to 207.104.44.21?

This is the only information I put into windows for it work, as provided by SBC:

IP: 207.104.44.21
Subnet: 255.255.255.240
Gateway: 67.124.9.185
Nameserver 206.13.31.12

Any help would be much appreciated, this has been frustrating me to no end for almost a week.

Did you restart inetd after changing the values?
Please post the output of ifconfig?
Try: ifconfig eth0 up.

Yea I tried everything. I finally found the problem though. After sitting back and thinking I realized the Gateway I had couldn't possibly work. After an hour on the phone trying to find a tech who knew what he was doing I found that the Gateway IP address needed to be 207.104.44.17. After I changed that everything worked like magic.

Edit: The reason I was so confused is because windows for some reason worked even with the wrong gateway

But I don't understand then why it worked with Windows.

Pity you didn't add IP addresses to the various nodes. It could have made things a bit clearer.

Now, a GATEWAY address must be part of the same subnet that the computer is in. So, this address 67.124.9.185 will not work for you. See below.

The 207.104.44.16 is completely allright. The route table shows the connected network routes. Your computer's IP address together with the netmask defines a range of IP addresses, the "subnet" you're in. Computers in the same subnet can communicate with each other without needing a "default gateway". When a computer wants to communicate with another host that has an IP address outside it's subnet, it will send these network packets to the "default gateway" which is a computer or a router that knows where to send these packets. The default gateway must have an IP address that fits in your computer's subnet range or it won't be found.

BTW, look here for the subnet information for your specific IP address/netmask: http://sox.homeip.net/cgi-bin/ipcalc...255.240&mask2=

The "0.0.0.0" address is equal to the term "default route" or "default gateway". And the definition of the default route is exactly what's missing from your route table, due to the incorrect GATEWAY value you used. Your computer will not be able to communicate with computers not in the local subnet.

Why that Windows box would have enough configuration data using only that setup of yours eludes me. The Windows box must learn or have configured a default gateway in some way. Most probably it is the IP address of the "Router" node in your network diagram.
What is the output in a DOS box of the command
Eric

EDIT: Sorry, Alien Bob managed to press the SEND button before me :)
And his answer is far way more complete than mine.

The problem is the gateway and the workstation must be in the same network.
You can't set a gateway=67.124.9.185 for a machine which ip=207.104.44.21.

Yep, I mentioned that I realised that. Took awhile to get through to someone at SBC who knew what gateway I should have been using. Thanks for the help guys :)

Space reserved

Why would inetd be involved at all????

Peace...

Sometimes, I have noticed, IP address changes and other things of that ilk do not reallychange (especially for the entire network) until you restart inetd. (More of a last ditch effort, tho. I would sometimes just reboot, just to be sure)

Strange. I wouldn't expect inetd to be related to lower-level networking functions at all. I mean the networking connections will have been established by the time inetd even starts.

Oh well, I don't run inetd so I guess I wouldn't notice any strange side-effects like this. :)

Peace...