 | | Re: A miracle happened [Was: Getting DHCP, IP aliasing and IP forwarding
to wo | Re: A miracle happened [Was: Getting DHCP, IP aliasing and IP forwarding
to wo 2003-11-09 - By Robert L Cochran
Back
So much for my interpretations of your routing table...
Bob
Vladimir G. Ivanovic wrote:
> My problem fixed itself. Yes, I know that this is incredible, but it 's
> true. I 'm currently investigating whether the recent rains (the first in
> about 6 months) brought some kind of aura over my computers. ;-)
>
> Another guess as to what happened is that my DHCP server 's iptables
> rejected pings, including pings that were supposed to be forwarded,
> hence the appearance of lack of connectivity. When I turned off
> iptables, I lost its forwarding capabilities so nothing appeared to have
> changed: I was still not connected. But the reason why I didn 't have
> connectivity changed. So my conclusion that turning iptables off had no
> effect was both correct and wrong.
>
> I also changed iptable 's dropping of ICMP packets to accepting them, but
> limiting the rate at which they would be accepted. That might also have
> had an effect.
>
> --- Vladimir
>
> -- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ----
> Vladimir G. Ivanovic
http://leonora.org/~vladimir
> 2770 Cowper St. vladimir@(protected)
> Palo Alto, CA 94306-2447 +1 650 678 8014
>
>
> > > > > > "vgi " == Vladimir G Ivanovic <vladimir@(protected) > writes:
>
>
> vgi > I can 't get my laptops to connect to the outside world, although they
> vgi > reach their DHCP server just fine.
> vgi >
> vgi > I 've not comprehended some facet or I must not haven 't done something
> vgi > (properly), but for the life of me I don 't know what it could be.
> vgi > Googling around has been helpful in getting to this point, but I 'm
> vgi > missing something. Your help is appreciated.
> vgi >
> vgi > Here 's where I am currently.
> vgi >
> vgi > Two laptops, the DHCP server, some other machines and a DSL modem are all
> vgi > connected to a 10/100 Mb Ethernet hub with the following IP addresses:
> vgi >
> vgi > network: 64.166.134.112
> vgi > netmask: 255.255.255.248
> vgi > DHCPserver: 64.166.134.117 (RH9)
> vgi > DSLmodem: 64.166.134.118
> vgi >
> vgi > network: 192.168.10.0
> vgi > netmask: 255.255.255.0
> vgi > laptop1: 192.168.10.109 (RH9)
> vgi > laptop2: 192.168.10.127 (WinXP)
> vgi >
> vgi > I set up the DHCP server 's routing table with three commands in /etc/rc.local:
> vgi >
> vgi > ifconfig eth0:1 192.168.10.1
> vgi > route add -host 192.168.10.1 eth0:1
> vgi > route add -net 192.168.10.0 netmask 255.255.255.0 eth0:1
> vgi >
> vgi > which gives this routing table:
> vgi >
> vgi > Destination Gateway Genmask Flags Metric Ref Use Iface
> vgi > 64.166.134.117 0.0.0.0 255.255.255.255 UH 0 0 0 eth0
> vgi > 192.168.10.1 0.0.0.0 255.255.255.255 UH 0 0 0 eth0
> vgi > 64.166.134.112 0.0.0.0 255.255.255.248 U 0 0 0 eth0
> vgi > 192.168.10.0 64.166.134.117 255.255.255.0 UG 0 0 0 eth0
> vgi > 169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth0
> vgi > 127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 lo
> vgi > 0.0.0.0 64.166.134.118 0.0.0.0 UG 0 0 0 eth0
> vgi >
> vgi > The DHCP server 's Ethernet network interface:
> vgi >
> vgi > eth0 Link encap:Ethernet HWaddr 00:E0:18:05:A9:68
> vgi > inet addr:64.166.134.117 Bcast:64.166.134.119 Mask:255.255.255.248
> vgi > UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
> vgi > RX packets:440089 errors:0 dropped:0 overruns:0 frame:0
> vgi > TX packets:409012 errors:0 dropped:0 overruns:1 carrier:0
> vgi > collisions:0 txqueuelen:100
> vgi > RX bytes:272871106 (260.2 Mb) TX bytes:94124015 (89.7 Mb)
> vgi > Interrupt:10 Base address:0xa800 Memory:ee800000-ee800038
> vgi >
> vgi > eth0:1 Link encap:Ethernet HWaddr 00:E0:18:05:A9:68
> vgi > inet addr:192.168.10.1 Bcast:192.168.10.255 Mask:255.255.255.0
> vgi > UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
> vgi > RX packets:440089 errors:0 dropped:0 overruns:0 frame:0
> vgi > TX packets:409012 errors:0 dropped:0 overruns:1 carrier:0
> vgi > collisions:0 txqueuelen:100
> vgi > RX bytes:272871106 (260.2 Mb) TX bytes:94124015 (89.7 Mb)
> vgi > Interrupt:10 Base address:0xa800 Memory:ee800000-ee800038
> vgi >
> vgi > and IP forwarding is turned on:
> vgi >
> vgi > # sysctl net.ipv4.ip_forward
> vgi > net.ipv4.ip_forward = 1
> vgi >
> vgi > DHCP is setup thusly (/etc/dhcpd.conf):
> vgi >
> vgi > default-lease-time 600;
> vgi > max-lease-time 7200;
> vgi > option subnet-mask 255.255.255.0;
> vgi > option broadcast-address 192.168.10.255;
> vgi > option routers 192.168.10.1;
> vgi > option domain-name-servers 64.166.134.117, 206.13.12.28, 206.13.31.12;
> vgi > option domain-name "leonora.org ";
> vgi > ddns-update-style ad-hoc;
> vgi >
> vgi > subnet 192.168.10.0 netmask 255.255.255.0 {
> vgi > range 192.168.10.2 192.168.10.254;
> vgi > host laptop1 {
> vgi > hardware ethernet 00:0b:db:1b:ca:5a;
> vgi > fixed-address 192.168.10.109;
> vgi > }
> vgi > host laptop2 {
> vgi > hardware ethernet 00:10:a4:03:dc:45;
> vgi > fixed-address 192.168.10.127;
> vgi > }
> vgi > }
> vgi >
> vgi > I 've entered the necessary mumbo-jumbo for iptables to work with my new
> vgi > eth0:1 interface, but I get the same behavior (no access from laptops
> vgi > to the Internet) even if I turn iptables off.
> vgi >
> vgi > Concentrating on laptop1, the Linux laptop, for the moment... The last
> vgi > entry in laptop1 's dhcp lease looks like this:
> vgi >
> vgi > lease {
> vgi > interface "eth0 ";
> vgi > fixed-address 192.168.10.109;
> vgi > option subnet-mask 255.255.255.0;
> vgi > option routers 192.168.10.1;
> vgi > option dhcp-lease-time 600;
> vgi > option dhcp-message-type 5;
> vgi > option domain-name-servers 64.166.134.117,206.13.12.28,206.13.31.12;
> vgi > option dhcp-server-identifier 64.166.134.117;
> vgi > option broadcast-address 192.168.10.255;
> vgi > option domain-name "leonora.org ";
> vgi > renew 0 2003/11/9 19:22:16;
> vgi > rebind 0 2003/11/9 19:26:27;
> vgi > expire 0 2003/11/9 19:27:42;
> vgi > }
> vgi >
> vgi > Its Ethernet interface is:
> vgi >
> vgi > eth0 Link encap:Ethernet HWaddr 00:0B:DB:1B:CA:5A
> vgi > inet addr:192.168.10.109 Bcast:192.168.10.255 Mask:255.255.255.0
> vgi > UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
> vgi > RX packets:128741 errors:0 dropped:0 overruns:0 frame:0
> vgi > TX packets:228979 errors:0 dropped:0 overruns:0 carrier:2
> vgi > collisions:0 txqueuelen:100
> vgi > RX bytes:10101993 (9.6 Mb) TX bytes:287682017 (274.3 Mb)
> vgi > Interrupt:10 Memory:e0100000-e0101080
> vgi >
> vgi > and its routing table is:
> vgi >
> vgi > Destination Gateway Genmask Flags Metric Ref Use Iface
> vgi > 192.168.10.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
> vgi > 169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth0
> vgi > 127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 lo
> vgi > 0.0.0.0 192.168.10.1 0.0.0.0 UG 0 0 0 eth0
> vgi >
> vgi > Hmmm. no host entry, but adding one with
> vgi >
> vgi > route add -host 192.168.10.109 eth0
> vgi >
> vgi > didn 't change any behavior I could detect.
> vgi >
> vgi > So, everything looks OK to me and I 've exhausted my knowledge. Any suggestions?
> vgi >
> vgi > --- Vladimir
> vgi >
> vgi > -- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ----
> vgi > Vladimir G. Ivanovic
http://leonora.org/~vladimir
> vgi > 2770 Cowper St. vladimir@(protected)
> vgi > Palo Alto, CA 94306-2447 +1 650 678 8014
> vgi >
> vgi >
> vgi > --
> vgi > Shrike-list mailing list
> vgi > Shrike-list@(protected)
> vgi > https://www.redhat.com/mailman/listinfo/shrike-list
> vgi >
>
>
--
Bob Cochran
Greenbelt, Maryland, USA
http://greenbeltcomputer.biz/
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