Ever since I moved to this ISP I've been having network problems, and I
need a little help.
They gave me an antique motorolla cable modem, and usually I have a
linksys router plugged into the router, but right now I have my FC4 pc
plugged in directly into the modem, to rule out any problems with the
router.
For the last couple of days the connection was ok, but this afternoon it
rained, and, since my ISP's service seems to depend on the weather, the
network went down. If it rains, it goes down, if it's windy, it goes down,
if there's lightening, you guessed it, it goes down. It's an ISP from hell.
Now I've configured eth0 with dhcp. It does get an IP address, but when I
try to connect anywhere, it says network unreachable:
ssh: connect to host cse port 22: Network is unreachable
I see network activity in gkrellm and I see ARP packets with ethereal,
so the link is ok. So I look at the routing table, and I see no default
gateway:
12) root:~> route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
24.35.40.0 0.0.0.0 255.255.248.0 U 0 0 0 eth0
169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth0
I have absolutely no idea where the 168.254.0.0 came from. I did see this
happening in windows, a long time ago. All I did in the network
configuration tool was to click on get IP automatically with dhcp.
Anyway, I did see some DHCP packets with ethereal coming in, among
countless ARP packets (Who has xxx, Tell yyy), so I figured that must be
the gateway. Manually, I do
route add default gateway xx.xx.xx.xx
and then voila! I'm online.
Now that I got this far, I want to pinpoint where the problem is.
Why am I not getting the default gateway? Is it some bug in my FC4 dhcp
client, or is my stupid ISP that's not sending it. Is it possible to tell?
For what it's worth, I installed the dhcp server on this machine (FC2,
just prior to FC4), and my other machines as well as the router got all
the required info just fine. I do want to go out through the router
though, and I want it to get all the info, as it should. I am positive my
hardware is ok, except possibly the motorolla cable modem, which is from
the ISP.
Below is the DHCP packet I saw with ethereal. Please someone help, before
I end up in a mad house.
No. Time Source Destination Protocol Info
4693 186.355671 24.35.40.1 255.255.255.255 DHCP DHCP Offer - Transaction ID 0x33d1a0
Frame 4693 (363 bytes on wire, 363 bytes captured)
Arrival Time: Jul 5, 2005 19:52:47.244828000
Time delta from previous packet: 0.120903000 seconds
Time since reference or first frame: 186.355671000 seconds
Frame Number: 4693
Packet Length: 363 bytes
Capture Length: 363 bytes
Protocols in frame: eth:ip:udp:bootp
Ethernet II, Src: 00:50:57:00:99:a6, Dst: ff:ff:ff:ff:ff:ff
Destination: ff:ff:ff:ff:ff:ff (Broadcast)
Source: 00:50:57:00:99:a6 (Broadban_00:99:a6)
Type: IP (0x0800)
Internet Protocol, Src Addr: 24.35.40.1 (24.35.40.1), Dst Addr: 255.255.255.255
(255.255.255.255)
Version: 4
Header length: 20 bytes
Differentiated Services Field: 0x07 (DSCP 0x01: Unknown DSCP; ECN: 0x03)
0000 01.. = Differentiated Services Codepoint: Unknown (0x01)
.... ..1. = ECN-Capable Transport (ECT): 1
.... ...1 = ECN-CE: 1
Total Length: 349
Identification: 0x0000 (0)
Flags: 0x00
0... = Reserved bit: Not set
.0.. = Don't fragment: Not set
..0. = More fragments: Not set
Fragment offset: 0
Time to live: 16
Protocol: UDP (0x11)
Header checksum: 0x6966 (correct)
Source: 24.35.40.1 (24.35.40.1)
Destination: 255.255.255.255 (255.255.255.255)
User Datagram Protocol, Src Port: bootps (67), Dst Port: bootpc (68)
Source port: bootps (67)
Destination port: bootpc (68)
Length: 329
Checksum: 0x6b77 (correct)
Bootstrap Protocol
Message type: Boot Reply (2)
Hardware type: Ethernet
Hardware address length: 6
Hops: 0
Transaction ID: 0x0033d1a0
Seconds elapsed: 0
Bootp flags: 0x8000 (Broadcast)
1... .... .... .... = Broadcast flag: Broadcast
.000 0000 0000 0000 = Reserved flags: 0x0000
Client IP address: 0.0.0.0 (0.0.0.0)
Your (client) IP address: 24.35.42.93 (24.35.42.93)
Next server IP address: 0.0.0.0 (0.0.0.0)
Relay agent IP address: 24.35.40.1 (24.35.40.1)
Client MAC address: 00:12:17:32:ea:79 (Cisco-Li_32:ea:79)
Server host name not given
Boot file name not given
Magic cookie: (OK)
Option 53: DHCP Message Type = DHCP Offer
Option 54: Server Identifier = 24.35.0.42
Option 51: IP Address Lease Time = 6 days, 23 hours, 59 minutes, 55 seconds
Option 1: Subnet Mask = 255.255.248.0
Option 5: Name Server
IP Address: 24.35.0.12
IP Address: 24.35.0.13
Option 23: Default IP Time-to-Live = 64
Option 27: All Subnets are Local = No
Option 28: Broadcast Address = 255.255.255.255
Option 31: Perform Router Discover = Enabled
Option 35: ARP Cache Timeout = 1 minute
Option 37: TCP Default TTL = 64
Option 3: Router = 24.35.40.1
Option 6: Domain Name Server
IP Address: 24.35.0.12
IP Address: 24.35.0.13
Option 44: NetBIOS over TCP/IP Name Server = 127.0.0.1
Option 46: NetBIOS over TCP/IP Node Type = H-node
End Option
