Duplicate packets on ping after installing SoftEther

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eric24
Posts: 6
Joined: Wed Jul 27, 2016 3:31 am

Duplicate packets on ping after installing SoftEther

Post by eric24 » Wed Jul 27, 2016 8:34 pm

After installing SoftEther on a Ubuntu Amazon EC2 instance, I noticed I'm getting duplicate responses when ping'ing the instance from another instance in the EC2 VPC. Upon further investigation, I see that the Ethernet device has promiscuous mode enabled:

eth0 Link encap:Ethernet HWaddr 0e:7c:2d:99:fc:a1
inet addr:172.30.3.216 Bcast:172.30.3.255 Mask:255.255.255.0
inet6 addr: fe80::c7c:2dff:fe99:fca1/64 Scope:Link
UP BROADCAST RUNNING PROMISC MULTICAST MTU:1500 Metric:1
RX packets:168090 errors:0 dropped:0 overruns:0 frame:0
TX packets:171989 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:28348362 (28.3 MB) TX bytes:27110208 (27.1 MB)

This is in spite of using SecureNAT and not having a local bridge defined.

However, disabling it via ifconfig eth0 -promisc doesn't stop the duplicate ping packets.

1) What's causing the duplicate pings?
2) Since promiscuous mode isn't supported on EC2, how do I configure SoftEther to not enable it in the first place?

Thank you!


[EDIT] I did verify that if I take the VPN server offline, I don't get duplicate ping responses.

thisjun
Posts: 2458
Joined: Mon Feb 24, 2014 11:03 am

Re: Duplicate packets on ping after installing SoftEther

Post by thisjun » Fri Aug 19, 2016 7:07 am

Where did you ping to and from?
What SecureNAT mode was used?

eric24
Posts: 6
Joined: Wed Jul 27, 2016 3:31 am

Re: Duplicate packets on ping after installing SoftEther

Post by eric24 » Tue Aug 23, 2016 7:01 pm

>> Where did you ping to and from?
To the EC2 instance that's running SoftEther from another EC2 instance in that same VPC.

>> What SecureNAT mode was used?
I'm not sure what you mean by "mode"?

thisjun
Posts: 2458
Joined: Mon Feb 24, 2014 11:03 am

Re: Duplicate packets on ping after installing SoftEther

Post by thisjun » Fri Sep 09, 2016 7:37 am

Please check SecureNAT Operating Status.

thisjun
Posts: 2458
Joined: Mon Feb 24, 2014 11:03 am

Re: Duplicate packets on ping after installing SoftEther

Post by thisjun » Thu Dec 15, 2016 7:04 am

Destination host and SecureNAT virtual host send ping reply when SecureNAT operating mode is raw IP mode.

Kooza
Posts: 1
Joined: Thu Nov 19, 2020 8:03 pm

Re: Duplicate packets on ping after installing SoftEther

Post by Kooza » Thu Nov 19, 2020 8:08 pm

Thanks, I have the same problem, I thought it was a problem, but now I can see that it is completely normal. Excellent product, excellent VPN solution.

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