Linux - NetworkingThis forum is for any issue related to networks or networking.
Routing, network cards, OSI, etc. Anything is fair game.
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I have some weird routing issue that I don't understand and can't solve.
I have an apache2 running on a debian7 machine in my homenetwork. my cablerouter forwards port 80 to that machine. people from the internet can access the websever. I can access it with the local 192.168.. address but I can't access it via the external ip.
somehow the server doesn't know how to answer back.
this is the server's routing table
Code:
philipp@scenicxb:~$ sudo route -n
Kernel-IP-Routentabelle
Ziel Router Genmask Flags Metric Ref Use Iface
0.0.0.0 192.168.0.1 0.0.0.0 UG 0 0 0 eth1
192.168.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1
I deleted the latter entry and when I do that I can access my webserver with the external ip but not anymore with the local ip.
What I'd want is to be able to access the service with either ip, internal or external.
I appreciate any help I can get.
Here is some more detailed information on the server's network setup. (eth0 is an unused nic) if you need any more info please tell me.
Code:
philipp@scenicxb:~$ sudo ifconfig -a
eth0 Link encap:Ethernet Hardware Adresse 00:30:05:2d:e9:68
BROADCAST MULTICAST MTU:1500 Metrik:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
Kollisionen:0 Sendewarteschlangenlänge:1000
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
eth1 Link encap:Ethernet Hardware Adresse 00:0c:f6:48:a9:1c
inet Adresse:192.168.0.187 Bcast:192.168.0.255 Maske:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metrik:1
RX packets:33816930 errors:0 dropped:0 overruns:0 frame:0
TX packets:40044411 errors:0 dropped:0 overruns:0 carrier:0
Kollisionen:0 Sendewarteschlangenlänge:1000
RX bytes:3983993477 (3.7 GiB) TX bytes:246395488 (234.9 MiB)
Interrupt:17 Basisadresse:0x3000
lo Link encap:Lokale Schleife
inet Adresse:127.0.0.1 Maske:255.0.0.0
UP LOOPBACK RUNNING MTU:16436 Metrik:1
RX packets:125 errors:0 dropped:0 overruns:0 frame:0
TX packets:125 errors:0 dropped:0 overruns:0 carrier:0
Kollisionen:0 Sendewarteschlangenlänge:0
RX bytes:7251 (7.0 KiB) TX bytes:7251 (7.0 KiB)
philipp@scenicxb:~$ cat /etc/network/interfaces
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).
# The loopback network interface
auto lo
iface lo inet loopback
# The primary network interface
#allow-hotplug eth1
auto eth1
iface eth1 inet static
address 192.168.0.187
netmask 255.255.255.0
gateway 192.168.0.1
philipp@scenicxb:~$ cat /etc/sysctl.d/disable-ipv6.conf
net.ipv6.conf.all.disable_ipv6=1
Last edited by Necrophagos; 02-24-2014 at 02:17 PM.
Run tcpdump on the server and the local host and check the source and dest addresses on the request and response. Most likely requests are forwarded through the router but responses are not being returned correctly because of address mismatch.
I tried to visit my server through the browser (using the external ip adress) and this was the output that tcpdump produced. there are occasions of incorrect checksums but I actually don't know what that means.
192.168.0.187 is the server
192.168.0.10 is the client
Last edited by Necrophagos; 02-24-2014 at 04:45 PM.
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