On Wed, 2005-07-06 at 01:02 -0400, Amadeus W. M. wrote: > 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 ---------------^^^^^^^^^^^^^^^^^^^^ That looks like the setting for the default gateway to me. > 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 Paul. -- Paul Howarth <paul@xxxxxxxxxxxx>
