Linux
無法在同一子網內 ping linux 網路命名空間
這是該問題的快速摘要。我無法與同一子網內的 linux 網路命名空間通信。我在無頭伺服器上執行 Ubuntu 14.04.1 LTS。我已經對此進行了大約一周的故障排除，因此在此先感謝您的任何回复。
從頭開始：（底部的tcpdump）
我有兩個物理介面
em1和em2. 我已經創建了兩個橋br0和br1. 第一個橋br0包含我的外部介面em1。第二個網橋br1包含我的內部介面em2，並且veth0（連結到如下所示veth1的網路命名空間。）vpn
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 # Bridge setup auto br0 em1 iface br0 inet dhcp bridge_ports em1 auto br1 em2 veth0 iface br1 inet static address 10.0.0.1 network 10.0.0.0 netmask 255.255.255.0 broadcast 10.0.0.255 bridge_ports em2 veth0 # pre and post up pre-up ip link add name veth0 type veth peer name veth1 pre-up ip netns add vpn pre-up ip link set veth1 netns vpn post-up ip netns exec vpn ip link set dev lo up post-up ip netns exec vpn ip link set dev veth1 up post-up ip netns exec vpn ip addr add 10.0.0.254/24 broadcast 10.0.0.255 dev veth1 post-up ip netns exec vpn ip route add default via 10.0.0.1我正在使用此伺服器進行路由。這是我的 nat.sh，每次啟動都會執行。
echo -e "\n\nLoading simple rc.firewall-iptables version $FWVER..\n" DEPMOD=/sbin/depmod MODPROBE=/sbin/modprobe EXTIF="br0" INTIF="br1" #INTIF2="eth0" echo " External Interface: $EXTIF" echo " Internal Interface: $INTIF" #====================================================================== #== No editing beyond this line is required for initial MASQ testing == echo -en " loading modules: " echo " - Verifying that all kernel modules are ok" $DEPMOD -a echo "----------------------------------------------------------------------" echo -en "ip_tables, " $MODPROBE ip_tables echo -en "nf_conntrack, " $MODPROBE nf_conntrack echo -en "nf_conntrack_ftp, " $MODPROBE nf_conntrack_ftp echo -en "nf_conntrack_irc, " $MODPROBE nf_conntrack_irc echo -en "iptable_nat, " $MODPROBE iptable_nat echo -en "nf_nat_ftp, " $MODPROBE nf_nat_ftp echo "----------------------------------------------------------------------" echo -e " Done loading modules.\n" echo " Enabling forwarding.." echo "1" > /proc/sys/net/ipv4/ip_forward echo " Enabling DynamicAddr.." echo "1" > /proc/sys/net/ipv4/ip_dynaddr echo " Clearing any existing rules and setting default policy.." iptables-restore <<-EOF *nat -A POSTROUTING -o "$EXTIF" -j MASQUERADE COMMIT *filter :INPUT ACCEPT [0:0] :FORWARD DROP [0:0] :OUTPUT ACCEPT [0:0] -A FORWARD -i "$EXTIF" -o "$INTIF" -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT -A FORWARD -i "$INTIF" -o "$EXTIF" -j ACCEPT -A FORWARD -j LOG COMMIT EOF echo -e "\nrc.firewall-iptables v$FWVER done.\n"網路上的所有設備都具有來自該伺服器的地址，並且位於同一子網中。一切都在完美地相互交流。我唯一的問題是沒有設備可以到達
veth1網路命名空間內vpn，即使它像其他所有設備一樣具有來自伺服器的地址和子網，甚至可以 ping google。例如，來自我的筆記型電腦，地址為
10.0.0.4. 該命令ping 10.0.0.1有效，並且ping 10.0.0.3（我的 Xbox）有效。但ping 10.0.0.254不起作用，即使它與其他一切都在同一個網路上。以下是一些附加資訊：
sysctl net.ipv4.ip_forwardnet.ipv4.ip_forward = 1
cat /proc/sys/net/ipv4/ip_forward1
ifconfigbr0 Link encap:Ethernet HWaddr 00:1e:67:ad:9e:1d inet addr:71.95.217.302 Bcast:255.255.255.255 Mask:255.255.254.0 inet6 addr: fe80::21e:67ff:fead:9e1d/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:57249 errors:0 dropped:0 overruns:0 frame:0 TX packets:17297 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:13724815 (13.7 MB) TX bytes:2606039 (2.6 MB) br1 Link encap:Ethernet HWaddr 00:1e:67:ad:9e:1e inet addr:10.0.0.1 Bcast:10.0.0.255 Mask:255.255.255.0 inet6 addr: fe80::21e:67ff:fead:9e1e/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:17716 errors:0 dropped:0 overruns:0 frame:0 TX packets:18625 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:2382424 (2.3 MB) TX bytes:11990075 (11.9 MB) em1 Link encap:Ethernet HWaddr 00:1e:67:ad:9e:1d UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:58804 errors:0 dropped:0 overruns:0 frame:0 TX packets:17304 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:14632304 (14.6 MB) TX bytes:2606465 (2.6 MB) Memory:b1200000-b1280000 em2 Link encap:Ethernet HWaddr 00:1e:67:ad:9e:1e UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:17636 errors:0 dropped:0 overruns:0 frame:0 TX packets:20125 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:2639201 (2.6 MB) TX bytes:12086082 (12.0 MB) Memory:b1100000-b1180000 lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:65536 Metric:1 RX packets:4775 errors:0 dropped:0 overruns:0 frame:0 TX packets:4775 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:939016 (939.0 KB) TX bytes:939016 (939.0 KB) veth0 Link encap:Ethernet HWaddr 4e:99:98:cc:48:6d inet6 addr: fe80::4c99:98ff:fecc:486d/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:75 errors:0 dropped:0 overruns:0 frame:0 TX packets:1902 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:6799 (6.7 KB) TX bytes:140261 (140.2 KB)
brctl show br0bridge name bridge id STP enabled interfaces br0 8000.001e67ad9e1d no em1
brctl show br1bridge name bridge id STP enabled interfaces br1 8000.001e67ad9e1e no em2 veth0
ip routedefault via 71.95.216.1 dev br0 10.0.0.0/24 dev br1 proto kernel scope link src 10.0.0.1 71.95.216.0/23 dev br0 proto kernel scope link src 71.95.217.302
routeKernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface default 71-95-216-1.sta 0.0.0.0 UG 0 0 0 br0 10.0.0.0 * 255.255.255.0 U 0 0 0 br1 71.95.216.0 * 255.255.254.0 U 0 0 0 br0
ip netns exec vpn ifconfiglo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:65536 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) veth1 Link encap:Ethernet HWaddr 3e:0a:b5:c6:f4:07 inet addr:10.0.0.254 Bcast:10.0.0.255 Mask:255.255.255.0 inet6 addr: fe80::3c0a:b5ff:fec6:f407/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:1987 errors:0 dropped:0 overruns:0 frame:0 TX packets:75 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:146530 (146.5 KB) TX bytes:6799 (6.7 KB)
ip netns exec vpn ip routedefault via 10.0.0.1 dev veth1 10.0.0.0/24 dev veth1 proto kernel scope link src 10.0.0.254
ip netns exec vpn routeKernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface default 10.0.0.1 0.0.0.0 UG 0 0 0 veth1 10.0.0.0 * 255.255.255.0 U 0 0 0 veth1我在執行時做了
ping 10.0.0.254一個10.0.0.4然後tcpdump -v -i br1 > filegreped 的 tcpdump 輸出文件10.0.0.254。您可以在此處查看整個 tcpdump（不長）http://pastebin.com/raw.php?i=Rs9dpw4V。21:07:55.648413 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 10.0.0.254 tell 10.0.0.4, length 46 21:07:55.648448 ARP, Ethernet (len 6), IPv4 (len 4), Reply 10.0.0.254 is-at 3e:0a:b5:c6:f4:07 (oui Unknown), length 28 10.0.0.4 > 10.0.0.254: ICMP echo request, id 11630, seq 0, length 64 10.0.0.4 > 10.0.0.254: ICMP echo request, id 11630, seq 1, length 64 10.0.0.4 > 10.0.0.254: ICMP echo request, id 11630, seq 2, length 64 10.0.0.4 > 10.0.0.254: ICMP echo request, id 11630, seq 3, length 64 10.0.0.4 > 10.0.0.254: ICMP echo request, id 11630, seq 4, length 64 10.0.0.4 > 10.0.0.254: ICMP echo request, id 11630, seq 5, length 64 10.0.0.4 > 10.0.0.254: ICMP echo request, id 11630, seq 6, length 64 10.0.0.4 > 10.0.0.254: ICMP echo request, id 11630, seq 7, length 64 10.0.0.4 > 10.0.0.254: ICMP echo request, id 11630, seq 8, length 64 10.0.0.4 > 10.0.0.254: ICMP echo request, id 11630, seq 9, length 64 10.0.0.4 > 10.0.0.254: ICMP echo request, id 11630, seq 10, length 64 10.0.0.4 > 10.0.0.254: ICMP echo request, id 11630, seq 11, length 64如果有任何遺漏的資訊，請告訴我。
編輯：
iptables -L -nvChain INPUT (policy ACCEPT 33M packets, 45G bytes) pkts bytes target prot opt in out source destination Chain FORWARD (policy DROP 17439 packets, 3112K bytes) pkts bytes target prot opt in out source destination 2640K 3411M ACCEPT all -- br0 br1 0.0.0.0/0 0.0.0.0/0 ctstate RELATED,ESTABLISHED 2470K 464M ACCEPT all -- br1 br0 0.0.0.0/0 0.0.0.0/0 17439 3112K LOG all -- * * 0.0.0.0/0 0.0.0.0/0 LOG flags 0 level 4 Chain OUTPUT (policy ACCEPT 21M packets, 35G bytes) pkts bytes target prot opt in out source destination
iptables -t nat -L -nvChain PREROUTING (policy ACCEPT 280K packets, 30M bytes) pkts bytes target prot opt in out source destination Chain INPUT (policy ACCEPT 187K packets, 22M bytes) pkts bytes target prot opt in out source destination Chain OUTPUT (policy ACCEPT 198K packets, 13M bytes) pkts bytes target prot opt in out source destination Chain POSTROUTING (policy ACCEPT 58488 packets, 3569K bytes) pkts bytes target prot opt in out source destination 222K 15M MASQUERADE all -- * br0 0.0.0.0/0 0.0.0.0/0
ip netns exec vpn arping -I veth1 -c 3 10.0.0.2ARPING 10.0.0.2 60 bytes from 90:72:40:05:79:87 (10.0.0.2): index=0 time=1.001 sec 60 bytes from 90:72:40:05:79:87 (10.0.0.2): index=1 time=1.001 sec 60 bytes from 90:72:40:05:79:87 (10.0.0.2): index=2 time=1.001 sec --- 10.0.0.2 statistics ---
arping -I br1 -c 3 10.0.0.254ARPING 10.0.0.254 42 bytes from 3e:0a:b5:c6:f4:07 (10.0.0.254): index=0 time=1.001 sec 42 bytes from 3e:0a:b5:c6:f4:07 (10.0.0.254): index=1 time=1.001 sec 42 bytes from 3e:0a:b5:c6:f4:07 (10.0.0.254): index=2 time=1.001 sec --- 10.0.0.254 statistics --- 3 packets transmitted, 3 packets received, 0% unanswered (0 extra)
我假設如果你這樣做
sudo iptables -L | grep policy，它會看起來像這樣：Chain INPUT (policy ACCEPT) Chain FORWARD (policy DROP) Chain OUTPUT (policy ACCEPT)如果你只是這樣做
iptables --policy FORWARD ACCEPT。您的問題將得到解決。但是在沒有正確設置 iptables 的情況下擁有伺服器可能很危險。因此，您可能需要參考這個精彩的指南來開始使用 iptables。