Internal network bridge to NAT not functioning after upgrade of VBox to 3.0.6

[Patrick O'Connor]

A simple scenario. Machine 2 has a nic card using internal network (csci360). Machine 1 has two nic cards eth1 using internal network (csci360) and eth1 using NAT (ip ~10.0.2.X). I have IP_FORWARDING enabled on Machine 1. Back in version 2.X I was able to send traffic from machine 2 to machine 1 through internal to the NAT and out the host and then the traffic would return correctly. Now in version 3.0.6, the traffic stops at the host machine and never sees the VM. If I send a request from machine 1, the traffic goes out and back fine. When sent from machine 2 through machine 1, it goes out and stops at the machine 1. Below is a tcpdump from the host OS. Lines 2-6 shows a ping from machine 1 and 7-8 show a ping from machine 2. It stops at line 8.

[root@jb356-7 ~]# tcpdump -vv|grep google.com
tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 96 bytes
16:53:54.680706 IP (tos 0x0, ttl 63, id 0, offset 0, flags [DF], proto UDP (17), length 56)
  jb356-7.csci.csusb.edu.46510 > echo.csci.csusb.edu.domain: [bad udp cksum 6258!] 21002+
  A? google.com. (28)
16:53:54.684916 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 240)
  echo.csci.csusb.edu.domain > jb356-7.csci.csusb.edu.46510: 21002 q: A? google.com. 3/4/4 google.com.
  A gw-in-f100.google.com, google.com.[|domain]
16:53:54.689610 IP (tos 0x0, ttl 63, id 0, offset 0, flags [DF], proto ICMP (1), length 84)
  jb356-7.csci.csusb.edu > gw-in-f100.google.com: ICMP echo request, id 17416, seq 1, length 64
16:53:54.777436 IP (tos 0x0, ttl 46, id 62822, offset 0, flags [none], proto ICMP (1), length 84)
  gw-in-f100.google.com > jb356-7.csci.csusb.edu: ICMP echo reply, id 17416, seq 1, length 64
16:55:06.830593 IP (tos 0x0, ttl 62, id 0, offset 0, flags [DF], proto UDP (17), length 56)
  jb356-7.csci.csusb.edu.56157 > echo.csci.csusb.edu.domain: [bad udp cksum 26cb!] 47510+
  A? google.com. (28)
16:55:06.834671 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 240)
  echo.csci.csusb.edu.domain > jb356-7.csci.csusb.edu.56157: 47510 q: A? google.com. 3/4/4 google.com.
  A pz-in-f100.google.com, google.com.[|domain]

The only change that was made was an upgrade of VBox and then this stops functioning.

[Patrick O'Connor]

machine 1

[Patrick O'Connor]

machine 2

[Patrick O'Connor]

This functioned in version 2.2.0 without any changes. I downgraded back to version 2.2.0 and all is well.

Version 2.2.4 also seems broken.

Thanks, Patrick

[vasily Levchenko]

Replying to oconnorp:

This functioned in version 2.2.0 without any changes. I downgraded back to version 2.2.0 and all is well.

Version 2.2.4 also seems broken.

Thanks, Patrick

Thanks for reporting, will try to reproduce it here.

[vasily Levchenko]

for record reproduced the problem locally.

[vasily Levchenko]

Does

# sysctl -w net.ipv4.conf.all.proxy_arp=1

on guest with NAT fix an issue for you?

[vasily Levchenko]

No response, closing. Please fill free to reopen.