NAT 1:1 Polycom VSX 7000

wesleylc1

Hi Steve, how are you?
I monitored a connection made by my videoconferencing system, using "pftop" CLI my polycom connects with the target, but "NO_TRAFFIC: SINGLE" communication errors occur.

PR        DIR SRC                                           DEST                                                   STATE                AGE       EXP     PKTS    BYTES
rsvp      In  192.168.40.251:0                              140.242.250.200:0                              NO_TRAFFIC:SINGLE       00:15:15  00:00:19        0        0
tcp       In  192.168.40.251:3233                           140.242.250.200:1720                          ESTABLISHED:ESTABLISHED  00:07:57  23:58:04       15     1096
tcp       Out 189.20.108.XX:3233                            140.242.250.200:1720                          ESTABLISHED:ESTABLISHED  00:07:57  23:58:04       15     1096
tcp       In  192.168.40.251:3234                           140.242.250.200:3242                          ESTABLISHED:ESTABLISHED  00:07:57  23:59:35      181    10480
tcp       Out 189.20.108.XX:3234                            140.242.250.200:3242                          ESTABLISHED:ESTABLISHED  00:07:57  23:59:35      181    10480
udp       In  192.168.40.251:3232                           140.242.250.200:3262                           NO_TRAFFIC:SINGLE       00:07:56  00:00:30    19850 13004860
udp       Out 189.20.108.XX:3232                            140.242.250.200:3262                               SINGLE:NO_TRAFFIC   00:07:56  00:00:30    19850 13004860
udp       In  192.168.40.251:3231                           140.242.250.200:3261                           NO_TRAFFIC:SINGLE       00:07:51  00:00:29       95     7220
udp       Out 189.20.108.XX:3231                            140.242.250.200:3261                               SINGLE:NO_TRAFFIC   00:07:51  00:00:29       95     7220
udp       In  192.168.40.251:3233                           140.242.250.200:3263                           NO_TRAFFIC:SINGLE       00:07:51  00:00:29       95     9120
udp       Out 189.20.108.XX:3233                            140.242.250.200:3263                               SINGLE:NO_TRAFFIC   00:07:51  00:00:29       95     9120
udp       In  192.168.40.251:3235                           140.242.250.200:3265                           NO_TRAFFIC:SINGLE       00:07:51  00:00:29       95     7220
udp       Out 189.20.108.XX:3235                            140.242.250.200:3265                               SINGLE:NO_TRAFFIC   00:07:51  00:00:29       95     7220
udp       In  192.168.40.251:3237                           140.242.250.200:3267                           NO_TRAFFIC:SINGLE       00:07:51  00:00:29       95     7240
udp       Out 189.20.108.XX:3237                            140.242.250.200:3267                               SINGLE:NO_TRAFFIC   00:07:51  00:00:29       95     7240

Best regards,
Wesley Santos

stephenw10

That's not necessarily an error but you would expect more traffic when it connects correctly.

I would bet it's sending it's internal private IP still we've seen that many many times. Including numerous times when a VoIP provider told us it definitely wasn't and we had to prove it was using packet captures.

We would need to see the SIP packets to be sure.

PM them to me if you prefer. I'll take a look when I have time.

Steve

wesleylc1

can i send you a .pcap packet capture for you to help analyze?

stephenw10

Yes, start a chat and attach it there.

wesleylc1

not allowed, your chat is restricted to people you follow only

Derelict

Post whatever it is you think is telling you that. If that is the case it should not be. People chat me all the time without following.

wesleylc1

ERROR
This user has restricted their chat messages. They must follow you before you can talk to them

stephenw10

Hmm, must have changed the default at a forum update or something. I've changed that setting now, try again.

Steve

wesleylc1

Your chat is now released.

wesleylc1

Dear, I made the capture available on Google Drive

stephenw10

Great I have that.

There are no SIP packets in there so I can't check that directly but it looks like it's still sending it's internal IP as the address to connect back to which can never work. For example:

And:

I won't to be any sort of expert in those protocols but from your description of the behaviour and the fact we see only outgoing RTP traffic in the pcap I think it is not configured to send the external IP.

You need to set that correctly in the Polycom device before it can work behind NAT.

Steve

wesleylc1

Hi, thanks for your effort to help solve my case.
Please can you explain if I used the filter correctly, I intended to monitor only LAN-ip traffic, using a filter for polycom IP address "192.168.40.251", when NAT requests occur, they should be caught in tcpdump using the command filter below?

tcpdump -nvxi re0 -w capture.pcap host 192.168.40.251

I captured packets from the WAN-ip interface, using a filter for WAN-ip and LAN-ip addresses, but when analyzing wireshark did not find NAT requests, I will forward the link of this packet in your chat.
I used the command below.

tcpdump -nvxi sk1 -w new.pcap "(host 189.20.108.XX or host 192.168.40.251)"

Best regards,
Wesley Santos

Derelict

It has nothing to do with the filter.

The PBX is telling the far side to connect back to 192.168.40.251 on port 3230 for RTP.

Obviously the far side cannot do that because that is your inside, non-routable, RFC1918 address.

You need to tell the PBX to send your outside WAN address there instead.

It is embedded in the SIP protocol. NAT can't translate it and there is no SIP ALG in pfSense to do it for you either.

wesleylc1

Hey man, how you doing?
I reviewed all NAT settings applied to "Polycom VSX 7000", also restored the applied settings and configured them again. I can not understand what I am configuring wrong with NAT inside the pfsense firewall, the polycom NAT settings are very simple, below are some pictures of the polycom NAT settings.

LAN properties.
Captura de tela de 2019-08-15 17-18-34.png

Polycom NAT Settings.
Captura de tela de 2019-08-15 17-18-12.png

Captura de tela de 2019-08-15 17-17-06.png
Best regards,
Wesley Santos

Derelict

Sorry. I don't read Portuguese.

Derelict

https://community.polycom.com/t5/Video-Endpoints/VSX-7000-Connection-Issue/td-p/36896

wesleylc1

Sorry, I replaced the images using English.

wesleylc1

Hello, I have this same problem reported by this person.
I performed all the steps and was only able to connect with the other end by clearing the "NAT is H.323 compliant" check box, but only audio is transmitted between both ends, when I leave this option selected, I can't connect audio / video.

1565900638171-captura-de-tela-de-2019-08-15-17-18-12.png

In fact, I have come to the conclusion that my firewall is blocking requests on the H323 protocol, do you suggest some maneuver to free all traffic coming under the H323 protocol?

Best regards,
Wesley Santos

stephenw10

It's very unlikely to be blocking it unless you have added rules. Do you see blocked traffic?

If you uncheck that and incoming audio streams then work then clearly the device is then sending the correct address for external clients to connect to.

The lack of video could be related or it could be a missing firewall rule for whatever port that is using.

Try getting a pcap with the audio functioning and see what other traffic is there on the WAN.

Steve

wesleylc1

Hi @stephenw10, how are you?
I cleared the "H.323 NAT Compatible" checkbox, performed a new capture, traffic seems to occur between both ends, but only audio traffic occurs, video traffic requires Polycom-enabled H323 protocol.
In your chat I sent a packet capture.

Best regards,
Wesley Santos