Messages

You can update safely. ISC is still very much there in 25.1.7.

I updated last night and nothing broke for me.

Thanks, this will give me some (more) time to look into the alternatives.

Is there a migration guide from ISC to either KEA or dnsmasq, rather than configuring either of these alternatives to ISC afresh as described in the guide?  I consider my DHCP setup rather basic, but since I am not familiar with either KEA or dnsmasq it will take me time to look into pros & cons of either and walk through the documentation.

At least, can I update 25.1.6_4 to 25.1.7 and continue using ISC just as it is configured for now, or will it be removed by the new DHCP package(s) and leave me with a broken configuration?

Probably not directly related to gateways config, but I thought I should post this just in case.  I also received the same red coloured "Danger Unexpected error check log for details" pop up when I started an update to 24.7.12 earlier today.  The update completed a minute or so later and the system rebooted fine.  I can't find a php error.  The dpinger works and monitors the gateways, before and after the update, so I don't know why popped up.

Ok, after digging a little deeper I did a packet capture on the Apps on my Android phone RTP & STUN are being blocked and some DNS queries on port 53.

I experienced a problem with RTP failing due to packet size on releases newer than 24.7, something to do with how fragmentation is now being processed.  As a workaround I had to edit the VoIP phone and remove enough codecs from its configuration to allow packets to go through.  Perhaps your problem is related?

I'm on release 24.7.4_1 now, but the same RTP fragmentation problem remains.   :(

I noticed something with ping which I can't recall if it was the same on 24.7.  When I ping using IPv4 to check MTU size, it complains  about the packet size (unless I use sudo):

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~ $ ping -4 -c 1 -D -s 1472 www.google.com
ping: packet size too large: 1472 > 56: Operation not permitted

However, no such problem with IPv6:

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~ $ ping -6 -c 1 -D -s 1452 www.google.com
PING(1500=40+8+1452 bytes) 2001:XXXXXXXXXXX --> 2a00:1450:4009:81f::2004
1460 bytes from 2a00:1450:4009:81f::2004, icmp_seq=0 hlim=120 time=6.121 ms

--- www.google.com ping statistics ---
1 packets transmitted, 1 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 6.121/6.121/6.121/0.000 ms

Could someone please confirm if ping packet size is meant to have this constraint on IPv4 only, or if it is a result of the later releases?

Last time I used this setup a 4/5G modem the ISP provided CGNAT, so my suggestion would not work.  If you set keep alives from your network hopefully the VPN will not drop out.

Sorry, my mistake....the opnsense SHOULD see the public ip right? (didn't tried yet)...now the wan has a static ip4 ip, should i put PPPoE?

Place the modem in fully bridged mode and configure the opnsense WAN interface with IPv4 PPPoE, adding your login credentials at the "PPPoE configuration" section of the WAN interface page.

My problem is that I have 3 vpn of the same provide implemented and working with a fall-back logic.

You will need to replicate this VPN configuration at the opnsense router.  A bridged modem device would perform no routing.  A double NAT configuration could break many services, not just VPN.

I don't have access to EETV or any BT offering to compare notes, but have a look at these configurations to get you started:

https://forum.opnsense.org/index.php?topic=23064.0
https://www.draytek.co.uk/support/guides/vigor-2860-vdsl-setup

If you have access to a BT HomeHub and it is working as expected with EETV, then you can login into its GUI to find the required router settings, then use these on opnsense.

No, opnsense is installed on bare metal and its igb0 NIC is connected directly with a CAT6 cable to the ONT.

I've had an on & off MTU configuration issue with opnsense for years now.  It used to be the case when I'd set WAN's PPPoE MTU on the GUI to 1508, this would push the MTU of igb0 to 1508 to allow 8 bytes for the PPPoE header+ID tag and leave 1500 bytes for the  payload through WAN.  Unlike meyergru I don't use VLAN, but if I did the VLAN tag would add another 4 bytes for the VLAN tag, increasing the frame size to 1500+8+4=1512.

At some point the WAN interface settings GUI no longer worked this way, so I'd set the MTU for igb0 manually to 1508 on the console, which would provide a 1500 MTU for the WAN interface.  Annoyingly, I'd have to repeat this operation after each update/upgrade of the opnsense firmware - the setting would not stick over a reboot.

For the last few months, up and including 24.7, the MTU setting had started to stick, so I didn't have to look into (re)setting it manually.

Anyway, after I saw the phone would also fail to work over IPv6 and spotted errors on the phone logs mentioning something about no PDU received, I thought it must be an MTU issue again.  I checked with ifconfig and the Interfaces GUI details and was surprised to see pppoe0 showing an MTU of 1508, instead of 1500.  The igb0 link also showed MTU 1508, as it should.  Both couldn't be right.  However, ping tests on the router showed the WAN MTU was indeed 1500:

~ # ping -6 -c 1 -D -s 1452 google.com
PING(1500=40+8+1452 bytes) 2001:XXXXXXXXXXXXXX --> 2a00:1450:4009:827::200e
1460 bytes from 2a00:1450:4009:827::200e, icmp_seq=0 hlim=120 time=5.871 ms

~ # ping -6 -c 1 -D -s 1453 google.com
PING(1501=40+8+1453 bytes) 2001:XXXXXXXXXXXXXX --> 2a00:1450:4009:827::200e
ping: sendmsg: Message too long
ping: wrote google.com 1461 chars, ret=-1

The above ping tests are no different when run with firmware 24.7, although with 24.7 the pppoe0 MTU is displayed correctly as 1500 not 1508.

Here is what I fail to understand:

Despite the displayed MTU size anomaly, ping tests indicate an effective WAN MTU of 1500 bytes with both 24.7 and 24.7.x - so why does a larger INVITE datagram go through fine on 24.7, but fails to do so with 24.7.x?  What else is at play here?

Up to this point, I still think that the outbound NAT rules are wrong one way or another. Maybe the DNS entries do not map to the suspected IPs, maybe it is even worse and he is behind CGNAT or other type of double NAT.

Perhaps my reasoning was wrong, but I was thinking all that changed to cause the phones to stop calling out was the opensense firmware update.  It could be the updates allowed for hidden errors in my configuration to show up, and/or perhaps something else was clashing with the latest firmware changes.  As it happened it was an MTU issue causing fragmentation.

Either way, thank you meyergru for your config suggestions, it helped me improve and tidy up my rules.

Thank you guys for all your help!  :)

TL;DR:  In my case the problem has been with the way the recent kernel changes have affected how the MTU is being processed.  Just to confirm, in my case I did not need a "static port", or additional outbound NAT beyond the automatically created NAT rules when setting Port Forwarding.  This is because in this case the phones and ISP's SIP gateway are 'smart' enough to acknowledge the SIP/RTP ports requested by the phones and use them reliably.

Since I started looking at this problem, I've spent some time checking firewall rules and trying all the different settings meyergru suggested, including "static port" for outbound NAT.  I tried setting a Hybrid Outbound rule with:

Destination address: any

and when it made no difference with:

Destination port: the ISP's SIP/RTP addresses.

Still no success.  I also removed port translation as recommended and took the opportunity to tidy up addresses in my aliases for the ISP's SIP/RTP gateway.  Without a usable VoIP setup I was heading back to the 24.7 firmware, but as a last thing before calling it a day I decided late yesterday to use IPv6, thinking this would allow me to do away with NATing and port forwarding complications, or potential configuration errors.  At this point I discovered with IPv6 the phone registration would fail altogether!  So instead of the IPv4 issue of just outgoing calls failing, with IPV6 the whole lot stopped working.  I suspected an opnsense MTU regression problem (has happened before), but ran out of time.

This morning I checked the WAN MTU and sure enough things looked different ...

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igb0: flags=1008843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST,LOWER_UP> metric 0 mtu 1508
        options=4802028<VLAN_MTU,JUMBO_MTU,WOL_MAGIC,HWSTATS,MEXTPG>
[snip ...]
pppoe0: flags=10088d1<UP,POINTOPOINT,RUNNING,NOARP,SIMPLEX,MULTICAST,LOWER_UP> metric 0 mtu 1508
        description: WAN (wan)


Then I saw BoodahsFever's post (thank you!), mentioning the INVITE packet size and how it can get larger with ever more RTP codecs added to it.  So I changed the phone settings to advertise only two codecs suitable for my ISP, which reduced a 1512 byte WAN packet down to 1376 and from then on outgoing calls became possible again.   :D

NOTE: Some months/years ago I had to keep setting the MTU manually using ifconfig on igb0 to 1508, so that the WAN PPPoe0 MTU would have a full IPv4 ethernet  payload of 1500.  Now ifconfig displays the ethernet MTU as 1508, but ping tests indicate it is still 1500.

Either way, should packet fragmentation break VoIP?

Something in the 24.7.x changes has caused my specific problem, but more applications/devices may be lurking out there similarly affected.  Is this something to be addressed in a future update?

Thank you for your patience meyergru,

It is encouraging to hear your VoIP works with the latest opnsense changes, there must be hope for mine too.   :)

Following your initial suggestion I had removed port translation for SIP, like this:

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                    Source              Destination                NAT
Interface Proto Address Ports   Address    Ports IP       Ports      Description
    WAN UDP SIP_IPv4   5060 (SIP) 123.45.6.789   5062         192.168.20.21 5062        SIP IPv4 redirect
    WAN UDP SIP_IPv4   5060 (SIP) 123.45.6.789   5064         192.168.20.22 5064        SIP IPv4 redirect

Just now, I additionally removed the 5060 SIP port for the ISP's source address:

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                    Source              Destination                NAT
Interface Proto Address Ports   Address    Ports IP       Ports      Description
    WAN UDP SIP_IPv4   * 123.45.6.789   5062         192.168.20.21 5062        SIP IPv4 redirect
    WAN UDP SIP_IPv4   * 123.45.6.789   5064         192.168.20.22 5064        SIP IPv4 redirect

123.45.6.789 is meant to show the obfuscated public address of my WAN interface.  SIP ports 5062 and 5064 are hardcoded respectively in the two VoIP phones, so these are the ports they use in their SIP communication with the ISP registrar.

Despite the above changes I am not able to place calls, although I continue to be able to register and receive calls.

Thanks meyergru,

I added two Outbound rules one for each phone.  I now have:

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nat on pppoe0 inet proto udp from 192.168.20.21 to <SIP_IPv4> -> (pppoe0:0) static-port
nat on pppoe0 inet proto udp from 192.168.20.22 to <SIP_IPv4> -> (pppoe0:0) static-port
[snip ...]
rdr on pppoe0 inet proto udp from <SIP_IPv4> port = sip to 123.45.6.789 port = 5062 -> 192.168.20.21 port 5062
rdr on pppoe0 inet proto udp from <SIP_IPv4> port = sip to 123.45.6.789 port = 5064 -> 192.168.20.22 port 5064
rdr on pppoe0 inet proto udp from <RTP_IPv4> to 123.45.6.789 port 49252:49262 -> 192.168.20.21 port 49252:49262
rdr on pppoe0 inet proto udp from <RTP_IPv4> to 123.45.6.789 port 49272:49282 -> 192.168.20.22 port 49272:49282

On 24.7 VoIP continues to work as expected.  I now upgraded to 24.7.3_1 and again I am not able to place an outbound call.

I wonder if I should just move these phones to IPv6 only, to do away with NAT problems.  TBH I have been avoiding doing it because IPv6 on opnsense has been a bit hit & miss over the years.

Is there anything else I should try configuring on 24.7.3_1 to solve this problem?

I've had a similar issue with Verizon and outgoing calls over "wifi calling." I have yet to find any setting I can change to make it work, but this has persisted for a very long time and isn't new in 24.7 for me.

Just to make it clear, the 24.7 and previous releases work OK in my use case, it's versions after 24.7 which partially broke VoIP here.  Are you able to receive calls with "wifi calling", or does it not work at all?

You did use "static port" for the connectiions?

Sorry, I am not familiar with many opnsense configuration options - are you referring to the Outbound NAT option to enable a "static port"?  I have not changed the Outbound NAT from 'auto'.  I only have one IPv4 public address at this moment.

Also, the SIP registrar responds to the correct ports for each phone, each phone registers successfully and incoming calls can be answered.  It is the outgoing calls which fail.