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umka69
Tux's lil' helper
Joined: 31 Mar 2013
Posts: 124
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 Posted: Wed Sep 24, 2014 4:05 pm Post subject: TUN/TAP networking |
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Hello.
I'm running several VMs over QEMU. Networking is configured by TUN/TAP devices.
It works but I can't rich one VM from another one.
host ICMP to internet = works
guest1 ICMP to hostnode or internet = works
guest2 ICMP to hostnode or internet = works
guest2 ICMP to guest1 = fails
There are two questions to comuity:
1. How to configurat TUN with /etc/conf.d/net for riching one VM from another?
2. Is TUN/TAP the best way in case of problem?
Configurations of host machine's environment:
| Code: | den ~ # cat /etc/conf.d/net
tuntap_tap0="tap"
tuntap_tap1="tap"
config_tap0="null"
config_tap1="null"
config_enp3s0="null"
config_br0="dhcp"
bridge_br0="enp3s0 tap0 tap1"
rc_net_br0_need="net.enp3s0 net.tap0 net.tap1"
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Hu
Moderator
Joined: 06 Mar 2007
Posts: 21631
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| Posted: Wed Sep 24, 2014 10:17 pm Post subject: |
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| Yes, TUN/TAP is a good choice here. What is the nature of the failure? What error messages appear when you try it? Can guest2 communicate with guest1 over any protocol? |
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vaxbrat
l33t
Joined: 05 Oct 2005
Posts: 731
Location: DC Burbs
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| Posted: Thu Sep 25, 2014 4:08 am Post subject: |
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Check your /etc/sysctl.conf file:
| Code: | # Disables packet forwarding
net.ipv4.ip_forward = 0
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Should be
| Code: |
# Enable packet forwarding
net.ipv4.ip_forward = 1
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and
| Code: | # Ignore ICMP broadcasts
#net.ipv4.icmp_echo_ignore_broadcasts = 1
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becomes
| Code: | # Don't Ignore ICMP broadcasts
net.ipv4.icmp_echo_ignore_broadcasts = 0
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also you want to enable spanning tree protocol on your bridge (stp on) in /etc/conf.d/net
| Code: | brctl_br0=( "setfd 0" "sethello 0" "stp on" )
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umka69
Tux's lil' helper
Joined: 31 Mar 2013
Posts: 124
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| Posted: Fri Sep 26, 2014 5:59 pm Post subject: |
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Thx, I did this. The same error after rebooting. 
HOST configs:
| Code: | HOST ~ # cat /etc/sysctl.conf
net.ipv4.ip_forward = 1
net.ipv4.conf.all.rp_filter = 1
net.ipv4.icmp_echo_ignore_broadcasts = 0
HOST ~ # iptables -L
Chain INPUT (policy ACCEPT)
target prot opt source destination
Chain FORWARD (policy ACCEPT)
target prot opt source destination
Chain OUTPUT (policy ACCEPT)
target prot opt source destination
HOST ~ # cat /etc/conf.d/net
tuntap_tap0="tap"
tuntap_tap1="tap"
config_tap0="null"
config_tap1="null"
config_enp3s0="null"
config_br0="dhcp"
# config_br0="192.168.1.1/24"
brctl_br0=( "setfd 0" "sethello 0" "stp on" )
mac_br0="aa:bb:cc:dd:ee:ff"
bridge_br0="enp3s0 tap0 tap1"
rc_net_br0_need="net.enp3s0 net.tap0 net.tap1"
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GUEST2 network status
| Code: | GUEST2 ~ # ping -c3 192.168.1.9
PING 192.168.1.9 (192.168.1.9) 56(84) bytes of data.
From 192.168.1.7: icmp_seq=1 Destination Host Unreachable
From 192.168.1.7: icmp_seq=2 Destination Host Unreachable
From 192.168.1.7: icmp_seq=3 Destination Host Unreachable
--- 192.168.1.9 ping statistics ---
3 packets transmitted, 0 received, +3 errors, 100% packet loss, time 1999ms
pipe 3
GUEST2 ~ # traceroute 192.168.1.9
traceroute to 192.168.1.9 (192.168.1.9), 30 hops max, 60 byte packets
1 192.168.1.7 (192.168.1.7) 3005.668 ms !H 3005.640 ms !H 3005.636 ms !H
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PS: GUEST2=192.168.1.7 GUEST1=192.168.1.9
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