About Azure:same packets will received with eth0 and eth1 at same time.

Question

About Azure:same packets will received with eth0 and eth1 at same time.

Michiteru Sugitani 85

Hello

we are making SIP servers with Linux on Azure.
I found problem as below.

if SIP client will sent request to SIP servers, it will send request twice.
normally, if SIP servers does not respond within 500 ms it will re send request.

but this time 2nd request sent same time or just after 0.000001 sec.

I fouid this on Liux server with chcking packet.

thre are 2 NICs, eth0 and eth1.

I didn't made eth1.

there is no file for eth1 on /etc/sysconfig/network-scripts
there is ifcfg-ens3 file and set for onboot=yes

eth1 doen't have address but send and receive packet.

it seem that same packets will received with eth0 and eth1 at same time.
I confirmed this using tcpdump..

I think this is cause of this problem that SIP server will receive request twice.

NIC is connected for VM and NSG.
sometimes it seem packet using both NICs

does it need eth1?
how to route for use same NIC for inbound and outbound?.

I concern behavior that if software receive same request from 2 NICs..

Best regards.
Michiteru

KapilAnanth-MSFT 49,616 Reputation points Microsoft Employee Moderator

2023-03-03T10:00:16.6933333+00:00
@Michiteru Sugitani

Welcome to the Microsoft Q&A Platform. Thank you for reaching out & I hope you are doing well.

I understand that you are seeing the same packet in two NICs of your Azure VM.

This should not be the case.

Unless and until the packet is directed at the secondary NIC, the packets will not land at the NIC.

I see you have mentioned "I didn't made eth1.".

Do you mean that the Azure Platform only has one NIC and somehow, the Linux OS shows eth0 and eth1?

Is that the case?

In case you have dual NICs on the platform,

Can you share the IP address of each NIC

Also, the packet capture that shows that the packets are received at both the NICs

Cheers,

Kapil

Michiteru Sugitani 85

Hi @KapilAnanth-MSFT

Thank you for your reply.

This is first time using Azure.
I need to increase knowledge how to use.

this should not be the case.yes

yes I agree with you.

why I noticed this problem because I'm using SIP debugging tool called sngrep and it is working on terminal.

sngrep is displaying 2 same incoming packet at same time.

when I saw this I think this is something strange...

so I checked packets using tcpdump with specify NIC for each eth0 and eth1.

then I got to know each NIC received same packet at same time.

$ sudo tcpdump -nvA -i eth0 port 6060
dropped privs to tcpdump
tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 262144 bytes
19:59:29.137939 IP (tos 0x20, ttl 52, id 55269, offset 0, flags [none], proto UDP (17), length 433)
    220.157.195.32.49436 > 10.1.1.4.6060: UDP, length 405
E ......4..t...
..........dOPTIONS sip:******@wcc1-staging.az.cba-japan.com SIP/2.0
Via: SIP/2.0/UDP 10.18.217.221:54339;branch=z9hG4bK.66e7df47;rport;alias
From: sip:sipsak@10.18.217.221:54339;tag=7ca4d8db
To: sip:******@wcc1-staging.az.cba-japan.com
Call-ID: 2091178203@10.18.217.221
CSeq: 1 OPTIONS
Contact: sip:sipsak@10.18.217.221:54339
Content-Length: 0
Max-Forwards: 70
User-Agent: sipsak 0.9.8.1
Accept: text/plain


19:59:29.138177 IP (tos 0x10, ttl 64, id 38463, offset 0, flags [DF], proto UDP (17), length 423)
    10.1.1.4.6060 > 220.157.195.32.49436: UDP, length 395
E....?@.@..3
...... .......gSIP/2.0 200 OK
Via: SIP/2.0/UDP 10.18.217.221:54339;received=220.157.195.32;branch=z9hG4bK.66e7df47;rport=49436;alias
From: sip:sipsak@10.18.217.221:54339;tag=7ca4d8db
To: sip:******@wcc1-staging.az.cba-japan.com;tag=7fd5.b461ed26f0d595205d183b4484e9d8ba
Call-ID: 2091178203@10.18.217.221
CSeq: 1 OPTIONS
Accept: */*
Accept-Language: en
Server: clusercc voip service
Content-Length: 0

$ sudo tcpdump -nvA -i eth1 port 6060
dropped privs to tcpdump
tcpdump: listening on eth1, link-type EN10MB (Ethernet), capture size 262144 bytes
19:59:29.138184 IP (tos 0x10, ttl 64, id 38463, offset 0, flags [DF], proto UDP (17), length 423)
    10.1.1.4.6060 > 220.157.195.32.49436: UDP, length 395
E....?@.@..3
...... .......gSIP/2.0 200 OK
Via: SIP/2.0/UDP 10.18.217.221:54339;received=220.157.195.32;branch=z9hG4bK.66e7df47;rport=49436;alias
From: sip:sipsak@10.18.217.221:54339;tag=7ca4d8db
To: sip:******@wcc1-staging.az.cba-japan.com;tag=7fd5.b461ed26f0d595205d183b4484e9d8ba
Call-ID: 2091178203@10.18.217.221
CSeq: 1 OPTIONS
Accept: */*
Accept-Language: en
Server: clusercc voip service
Content-Length: 0

so I tried to down for eth1 using nmcli command and result is "no active connection".

yes on Azure portal there is only 1 NIC.

but there is file on /etc/sysconfig/network-scriots as ifcfg-ens3.

and has set as onboot=yes.

but ifconfig command is showing NIC as eth0 and eh1 like below.

eth1 has no address but receive and send packets.

sorry for my english because I'm from Japan.

$ ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 10.1.1.4  netmask 255.255.255.0  broadcast 10.1.1.255
        inet6 fe80::222:48ff:fe66:db2d  prefixlen 64  scopeid 0x20<link>
        ether 00:22:48:66:db:2d  txqueuelen 1000  (Ethernet)
        RX packets 4474428  bytes 1446426536 (1.3 GiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 3867764  bytes 2715273037 (2.5 GiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

eth1: flags=6211<UP,BROADCAST,RUNNING,SLAVE,MULTICAST>  mtu 1500
        ether 00:22:48:66:db:2d  txqueuelen 1000  (Ethernet)
        RX packets 4197810  bytes 1379494358 (1.2 GiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 5195024  bytes 2792184810 (2.6 GiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

Michiteru Sugitani 85

Hi @KapilAnanth-MSFT

MAC address are same for eth0 and eth1.
so 2 NIC will receive same packets. I think.
but only 1 NIC on portal.

eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 10.1.1.4  netmask 255.255.255.0  broadcast 10.1.1.255
        inet6 fe80::222:48ff:fe66:db2d  prefixlen 64  scopeid 0x20<link>
        ether 00:22:48:66:db:2d  txqueuelen 1000  (Ethernet)
        RX packets 7421  bytes 1455485 (1.3 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 7355  bytes 4554640 (4.3 MiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

eth1: flags=6211<UP,BROADCAST,RUNNING,SLAVE,MULTICAST>  mtu 1500
        ether 00:22:48:66:db:2d  txqueuelen 1000  (Ethernet)
        RX packets 6408  bytes 1257665 (1.1 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 9338  bytes 4685105 (4.4 MiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

KapilAnanth-MSFT 49,616 Reputation points Microsoft Employee Moderator

2023-03-03T12:47:54.1+00:00

@Michiteru Sugitani

I see you have removed a comment.

Not sure if this is by mistake or a platform issue, however, I shall try to address the comment.

You have confirmed that the Azure platform has only one NIC.

This indicates that the issue is completely OS related, or Application related.

The secondary NIC/IP could be a virtual IP created by the application for successful running or some other configuration added this.

In any case, the configuration of two NICs should not exist for a general case.

Again, it will not be feasible to comment on this behavior without understanding the nature of the Linux image you are using nor the application running.

If you are in a TestEnvironment, I would suggest you remove the NIC2, i.e, eth1 and check the working of the setup

Cheers,

Kapil
Michiteru Sugitani 85 Reputation points

2023-03-03T12:54:58.37+00:00

$ sudo nmcli device

DEVICE TYPE STATE CONNECTION

eth0 ethernet connected System eth0

eth1 ethernet unmanaged --

lo loopback unmanaged --
Michiteru Sugitani 85 Reputation points

2023-03-03T12:59:11.8933333+00:00

HI @KapilAnanth-MSFT

Thank you your advice.

how to delete eth1?
because on file for eth1 on this host.
I tried to remove ifcfg-ens3 and then reboot.
but eth1 is still there.

$ sudo nmcli device

DEVICE TYPE STATE CONNECTION

eth0 ethernet connected System eth0

eth1 ethernet unmanaged --

lo loopback unmanaged --
KapilAnanth-MSFT 49,616 Reputation points Microsoft Employee Moderator

2023-03-03T13:02:06.8366667+00:00

@Michiteru Sugitani

I am afraid that completely depends on the OS you are using.

May I ask what Linux distros are you using?
Michiteru Sugitani 85 Reputation points

2023-03-03T13:04:06.91+00:00

Hi @KapilAnanth-MSFT

I posted but it will gone....
how to delete eth1?
because no setting file for eth1....
I tried to remove ifcfg-ens3 and reboot but eth1 is still there.
Michiteru Sugitani 85 Reputation points

2023-03-03T13:05:08.8333333+00:00

Hi @KapilAnanth-MSFT

I'm using Rocky Linux 8 from Market place.
KapilAnanth-MSFT 49,616 Reputation points Microsoft Employee Moderator

2023-03-03T13:13:43.48+00:00

@Michiteru Sugitani

At this stage, I think we will need a specialized 1:1 session, where a support engineer can have a screen share session to pinpoint the issue. If you have a support plan you may file a support ticket, else please do let us know, we will try and help you get a one-time free technical support.

In case you need a one-time free technical support could you please send an email to azcommunity[At]microsoft[Dot]com with the below details.

Subject : Attn Kaananth | same packets will received with eth0 and eth1 at same time

Thread URL: Link to this thread.

Subscription ID : Subscription ID where the Azure VM is deployed.

P.S: You should have a Support Contributor or higher permission to create a support request.

Cheers,

Kapil
Michiteru Sugitani 85 Reputation points

2023-03-03T13:15:08.7133333+00:00

HI @KapilAnanth-MSFT

I made 3 VMs using Rocky Linux 8 official from Marketplace.
this problem occurred on 3 VMs.
KapilAnanth-MSFT 49,616 Reputation points Microsoft Employee Moderator

2023-03-03T13:21:19.78+00:00

@Michiteru Sugitani

Still, this does not eliminate the OS or application as the culprit.

So, I would urge you to go ahead with a Support Request as mentioned above.

Cheers,

Kapil
Michiteru Sugitani 85 Reputation points

2023-03-03T14:21:00.4133333+00:00

Hi @KapilAnanth-MSFT

thank you for taking log time.
I sent support request via Email.

Thank you.

Accepted answer

1 additional answer

Your answer

KapilAnanth-MSFT 49,616 Reputation points Microsoft Employee Moderator

2023-03-03T10:00:16.6933333+00:00

@Michiteru Sugitani

Welcome to the Microsoft Q&A Platform. Thank you for reaching out & I hope you are doing well.

I understand that you are seeing the same packet in two NICs of your Azure VM.

This should not be the case.

Unless and until the packet is directed at the secondary NIC, the packets will not land at the NIC.

I see you have mentioned "I didn't made eth1.".

Do you mean that the Azure Platform only has one NIC and somehow, the Linux OS shows eth0 and eth1?

Is that the case?

In case you have dual NICs on the platform,

Can you share the IP address of each NIC

Also, the packet capture that shows that the packets are received at both the NICs

Cheers,

Kapil
Michiteru Sugitani 85 Reputation points

2023-03-03T12:43:41.6533333+00:00

Hi @KapilAnanth-MSFT

MAC address are same for eth0 and eth1.
so 2 NIC will receive same packets. I think.
but only 1 NIC on portal.

eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 10.1.1.4 netmask 255.255.255.0 broadcast 10.1.1.255 inet6 fe80::222:48ff:fe66:db2d prefixlen 64 scopeid 0x20<link> ether 00:22:48:66:db:2d txqueuelen 1000 (Ethernet) RX packets 7421 bytes 1455485 (1.3 MiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 7355 bytes 4554640 (4.3 MiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 eth1: flags=6211<UP,BROADCAST,RUNNING,SLAVE,MULTICAST> mtu 1500 ether 00:22:48:66:db:2d txqueuelen 1000 (Ethernet) RX packets 6408 bytes 1257665 (1.1 MiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 9338 bytes 4685105 (4.4 MiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
KapilAnanth-MSFT 49,616 Reputation points Microsoft Employee Moderator

2023-03-03T12:47:54.1+00:00

@Michiteru Sugitani

I see you have removed a comment.

Not sure if this is by mistake or a platform issue, however, I shall try to address the comment.

You have confirmed that the Azure platform has only one NIC.

This indicates that the issue is completely OS related, or Application related.

The secondary NIC/IP could be a virtual IP created by the application for successful running or some other configuration added this.

In any case, the configuration of two NICs should not exist for a general case.

Again, it will not be feasible to comment on this behavior without understanding the nature of the Linux image you are using nor the application running.

If you are in a TestEnvironment, I would suggest you remove the NIC2, i.e, eth1 and check the working of the setup

Cheers,

Kapil
Michiteru Sugitani 85 Reputation points

2023-03-03T12:54:58.37+00:00

$ sudo nmcli device

DEVICE TYPE STATE CONNECTION

eth0 ethernet connected System eth0

eth1 ethernet unmanaged --

lo loopback unmanaged --
Michiteru Sugitani 85 Reputation points

2023-03-03T12:59:11.8933333+00:00

HI @KapilAnanth-MSFT

Thank you your advice.

how to delete eth1?
because on file for eth1 on this host.
I tried to remove ifcfg-ens3 and then reboot.
but eth1 is still there.

$ sudo nmcli device

DEVICE TYPE STATE CONNECTION

eth0 ethernet connected System eth0

eth1 ethernet unmanaged --

lo loopback unmanaged --
KapilAnanth-MSFT 49,616 Reputation points Microsoft Employee Moderator

2023-03-03T13:02:06.8366667+00:00

@Michiteru Sugitani

I am afraid that completely depends on the OS you are using.

May I ask what Linux distros are you using?
Michiteru Sugitani 85 Reputation points

2023-03-03T13:04:06.91+00:00

Hi @KapilAnanth-MSFT

I posted but it will gone....
how to delete eth1?
because no setting file for eth1....
I tried to remove ifcfg-ens3 and reboot but eth1 is still there.
Michiteru Sugitani 85 Reputation points

2023-03-03T13:05:08.8333333+00:00

Hi @KapilAnanth-MSFT

I'm using Rocky Linux 8 from Market place.
KapilAnanth-MSFT 49,616 Reputation points Microsoft Employee Moderator

2023-03-03T13:13:43.48+00:00

@Michiteru Sugitani

At this stage, I think we will need a specialized 1:1 session, where a support engineer can have a screen share session to pinpoint the issue. If you have a support plan you may file a support ticket, else please do let us know, we will try and help you get a one-time free technical support.

In case you need a one-time free technical support could you please send an email to azcommunity[At]microsoft[Dot]com with the below details.

Subject : Attn Kaananth | same packets will received with eth0 and eth1 at same time

Thread URL: Link to this thread.

Subscription ID : Subscription ID where the Azure VM is deployed.

P.S: You should have a Support Contributor or higher permission to create a support request.

Cheers,

Kapil
Michiteru Sugitani 85 Reputation points

2023-03-03T13:15:08.7133333+00:00

HI @KapilAnanth-MSFT

I made 3 VMs using Rocky Linux 8 official from Marketplace.
this problem occurred on 3 VMs.
KapilAnanth-MSFT 49,616 Reputation points Microsoft Employee Moderator

2023-03-03T13:21:19.78+00:00

@Michiteru Sugitani

Still, this does not eliminate the OS or application as the culprit.

So, I would urge you to go ahead with a Support Request as mentioned above.

Cheers,

Kapil
Michiteru Sugitani 85 Reputation points

2023-03-03T14:21:00.4133333+00:00

Hi @KapilAnanth-MSFT

thank you for taking log time.
I sent support request via Email.

Thank you.

Answer 1

@Michiteru Sugitani

Welcome to the Microsoft Q&A Platform. Thank you for reaching out & I hope you are doing well.

I understand that you are seeing the same packet in two NICs of your Azure VM.

Ideally, this shouldn't be the case.

You have confirmed that the Azure platform has only one NIC.

This raises the suspicion that the issue is either OS related, or Application related.

Hence I suggested to reach out to Azure Support Team and it appears they were able to resolve the issue.

Thanks,

Kapil

Please don’t forget to close the thread by clicking "Accept the answer" wherever the information provided helps you, as this can be beneficial to other community members.

Answer 2

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About Azure:same packets will received with eth0 and eth1 at same time.

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