networking – Ubuntu transmits TTL 0 multicast packets

IP packets with TTL 0 shall not leave host.

But when I start application which multicasts UDP packets with TTL 0, I see packets with TTL 0 leaving host for few seconds, and coming to normal behavior of TTL 0. This most likely happens after reboot and first start of application.

I confirmed packets with TTL 0 leaving host with tcpdump:

05:31:39.048304 IP (tos 0x0, id 14487, offset 0, flags (DF), proto UDP (17), length 1344)
    192.168.1.200.46968 > 239.0.0.1.1234: UDP, length 1316
05:31:39.049594 IP (tos 0x0, id 14488, offset 0, flags (DF), proto UDP (17), length 1344)
    192.168.1.200.46968 > 239.0.0.1.1234: UDP, length 1316
05:31:39.051601 IP (tos 0x0, id 14489, offset 0, flags (DF), proto UDP (17), length 1344)
    192.168.1.200.46968 > 239.0.0.1.1234: UDP, length 1316
05:31:39.053584 IP (tos 0x0, id 14490, offset 0, flags (DF), proto UDP (17), length 1344)
    192.168.1.200.46968 > 239.0.0.1.1234: UDP, length 1316

As we can see ttl is not displayed which means TTL 0, as confirmed from tcpdump man page: https://www.tcpdump.org/manpages/tcpdump.1.html (search ttl, it clearly indicated: ttl is the time-to-live; it is not reported if it is zero).

There are no any iptables rules running.

uname -a: Linux mydevice 4.15.0-101-generic #102-Ubuntu SMP Mon May 11 10:07:26 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux

lsb_release -a:

No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 18.04.4 LTS
Release:        18.04
Codename:       bionic

What can be the cause for this behavior, and how can I resolve this?

cisco – Why do I get all multicast traffic and how can I restrict it to a specific VLAN?

I have a small network in my house that contains 1x router, 2x switch, 1x AP, some computers and phones. Aa I also have two servers in the cluster (Proxmox) and a QNAP NAS storage in which I save my files.

I started using IPTV a few months ago. I have an Amiko set-top box and use it to watch IPTV television with Kodi. This box is on vlan6 (192.168.40.0/24) (which is in the LAN segment of the picture) because I know that the IPTV traffic should be in a separate vlan.

Below is a logical view of the entire network:
(Https://i.postimg.cc/Vkck6HB1/Home-networking.jpg)(1)

As you can see, I use Mikrotik hEX as the main router to cancel the internet service provider's public IP address and to do firewall, NAT and routing tasks. Since the Internet is terminated here, I expect some multicast traffic due to IPTV, I have also activated Mikrotik vlan6, but let's see the configuration of the ports:

(admin@hellhound.home.lan) > interface print
Flags: D - dynamic, X - disabled, R - running, S - slave
 #     NAME                                TYPE       ACTUAL-MTU L2MTU  MAX-L2MTU MAC-ADDRESS
 0  R  ;;; Link to ISP
       ether1                              ether            1500  1596       2026 B8:69:F4:DB:DA:1A
 1  RS ;;; Link to Cisco switch
       ether2                              ether            1500  1596       2026 6C:3B:6B:59:94:1D
 2  RS ;;; Link to Mikrotik access point
       ether3                              ether            1500  1596       2026 6C:3B:6B:59:94:1E
 3  X  ;;; Unused
       ether4                              ether            1500  1596       2026 6C:3B:6B:59:94:1F
 4  X  ;;; Unused
       ether5                              ether            1500  1596       2026 6C:3B:6B:59:94:20
 5  R  bridge                              bridge           1500  1596            6C:3B:6B:59:94:1D
 7  R  ;;; Vlan2 (192.168.0.0/24)
       vlan2-tag                           vlan             1500  1592            6C:3B:6B:59:94:1D
 8  R  ;;; Vlan3 (192.168.10.0/24)
       vlan3-tag                           vlan             1500  1592            6C:3B:6B:59:94:1D
 9  R  ;;; Vlan4 (192.168.20.0/24)
       vlan4-tag                           vlan             1500  1592            6C:3B:6B:59:94:1D
10  R  ;;; Vlan5 (192.168.30.0/24)
       vlan5-tag                           vlan             1500  1592            6C:3B:6B:59:94:1D
11  R  ;;; Vlan6 (192.168.40.0/24)
       vlan6-tag                           vlan             1500  1592            6C:3B:6B:59:94:1D
(admin@hellhound.home.lan) >

Below you will find detailed information on the interfaces:

(admin@hellhound.home.lan) >

 1 RS ;;; Link to Cisco switch
      name="ether2" driver-rx-byte=8 086 346 162 985 driver-rx-packet=8 497 403 137 driver-tx-byte=9 773 452 609 711 driver-tx-packet=9 060 307 937 rx-bytes=8 136 450 389 192
      rx-packet=8 500 830 242 rx-too-short=0 rx-64=300 056 rx-65-127=3 184 053 446 rx-128-255=32 101 321 rx-256-511=108 841 856 rx-512-1023=15 702 206 rx-1024-1518=5 167 902 503
      rx-too-long=0 rx-broadcast=635 679 rx-pause=0 rx-multicast=7 435 462 rx-fcs-error=0 rx-align-error=0 rx-fragment=0 rx-jabber=0 rx-drop=0 tx-bytes=9 809 890 367 273
      tx-packet=9 058 500 770 tx-64=84 233 804 tx-65-127=2 421 432 836 tx-128-255=42 937 817 tx-256-511=137 437 551 tx-512-1023=47 563 760 tx-1024-1518=6 326 702 104 tx-broadcast=230 527
      tx-pause=0 tx-multicast=1 576 570 tx-collision=0 tx-excessive-collision=0 tx-multiple-collision=0 tx-single-collision=0 tx-deferred=0 tx-late-collision=0 tx-drop=0 tx-fcs-error=0

 2 RS ;;; Link to Mikrotik access point
      name="ether3" driver-rx-byte=24 904 213 698 driver-rx-packet=31 434 954 driver-tx-byte=117 049 286 733 driver-tx-packet=86 389 672 rx-bytes=25 030 676 572 rx-packet=31 351 349
      rx-too-short=0 rx-64=9 944 483 rx-65-127=1 899 968 rx-128-255=3 695 745 rx-256-511=328 864 rx-512-1023=130 332 rx-1024-1518=15 440 208 rx-too-long=0 rx-broadcast=11 047 rx-pause=0
      rx-multicast=77 204 rx-fcs-error=0 rx-align-error=0 rx-fragment=0 rx-jabber=0 rx-drop=0 tx-bytes=117 408 472 688 tx-packet=84 677 640 tx-64=5 586 151 tx-65-127=2 562 504
      tx-128-255=807 744 tx-256-511=482 810 tx-512-1023=335 192 tx-1024-1518=76 615 271 tx-broadcast=121 167 tx-pause=0 tx-multicast=1 590 865 tx-collision=0 tx-excessive-collision=0
      tx-multiple-collision=0 tx-single-collision=0 tx-deferred=0 tx-late-collision=0 tx-drop=0 tx-fcs-error=0

Ok, there is a bridge over which I created VLAN tags:
(Https://i.postimg.cc/RVp3XztR/Mikrotik-h-EX-Bridge.jpg)(1)

As you can see, I'm sending all vlans to the Cisco switch. And I only tag vlan2 and vlan4 to the AP. So I don't expect multicast traffic on the AP interface, but in fact I do. I don't know why ..

(Https://i.postimg.cc/y8XYSXvR/Mikrotik-h-EX-Ether3-Winbox.jpg)(1)

See how much multicast traffic I have on ether3 connected to ether1 on AP. I can display different images with the same kind of information:

(Https://i.postimg.cc/grbmxnh4/Mikrotik-h-EX-Ether3.jpg)(1)

Ok, we didn't say anything about Cisco devices, here is the configuration:

interface GigabitEthernet0/1
 description Cisco-SG200-08
 switchport trunk allowed vlan 2-6
 switchport mode trunk
!
interface GigabitEthernet0/2
 description Do-Not-Work
 shutdown
!
interface GigabitEthernet0/3
 description QNAP-TS-431P
 switchport access vlan 2
 switchport mode access
!
interface GigabitEthernet0/4
 description MikroTik-hEX
 switchport mode trunk
!
interface GigabitEthernet0/5
 description proxmox-node-1
 switchport trunk native vlan 7
 switchport mode trunk
!
interface GigabitEthernet0/6
 description proxmox-node-2
 switchport trunk native vlan 7
 switchport mode trunk
!

interface Vlan1
 no ip address
!
interface Vlan2
 no ip address
!
interface Vlan3
 no ip address
!
interface Vlan4
 no ip address
!
interface Vlan5
 ip address 192.168.30.6 255.255.255.0
!
interface Vlan6
 no ip address
!

Below is a detailed interview view of the Cisco switch:

2960g#show interfaces GigabitEthernet 0/1
GigabitEthernet0/1 is up, line protocol is up (connected)
  Hardware is Gigabit Ethernet, address is 0022.bd38.b481 (bia 0022.bd38.b481)
  Description: Cisco-SG200-08
  MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive set (10 sec)
  Full-duplex, 1000Mb/s, media type is 10/100/1000BaseTX
  input flow-control is off, output flow-control is unsupported
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:00:00, output 00:00:00, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 367
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 2000 bits/sec, 2 packets/sec
     71462641 packets input, 34064842246 bytes, 0 no buffer
     Received 1185327 broadcasts (1173073 multicasts)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 1173073 multicast, 0 pause input
     0 input packets with dribble condition detected
     179474379 packets output, 252015506771 bytes, 0 underruns
     0 output errors, 0 collisions, 1 interface resets
     0 babbles, 0 late collision, 0 deferred
     0 lost carrier, 0 no carrier, 0 PAUSE output
     0 output buffer failures, 0 output buffers swapped out
2960g#

2960g#show interfaces GigabitEthernet0/3
GigabitEthernet0/3 is up, line protocol is up (connected)
  Hardware is Gigabit Ethernet, address is 0022.bd38.b483 (bia 0022.bd38.b483)
  Description: QNAP-TS-431P
  MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive set (10 sec)
  Full-duplex, 1000Mb/s, media type is 10/100/1000BaseTX
  input flow-control is off, output flow-control is unsupported
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:00:04, output 00:00:01, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 435
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 62000 bits/sec, 7 packets/sec
  5 minute output rate 55000 bits/sec, 13 packets/sec
     1870379854 packets input, 2240692066739 bytes, 0 no buffer
     Received 141380 broadcasts (101038 multicasts)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 101038 multicast, 119 pause input
     0 input packets with dribble condition detected
     1923167326 packets output, 1771972517143 bytes, 0 underruns
     0 output errors, 0 collisions, 1 interface resets
     0 babbles, 0 late collision, 0 deferred
     0 lost carrier, 0 no carrier, 0 PAUSE output
     0 output buffer failures, 0 output buffers swapped out
2960g#

GigabitEthernet0/4 is up, line protocol is up (connected)
  Hardware is Gigabit Ethernet, address is 0022.bd38.b484 (bia 0022.bd38.b484)
  Description: MikroTik-hEX
  MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
     reliability 255/255, txload 6/255, rxload 6/255
  Encapsulation ARPA, loopback not set
  Keepalive set (10 sec)
  Full-duplex, 1000Mb/s, media type is 10/100/1000BaseTX
  input flow-control is off, output flow-control is unsupported
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:00:01, output 00:00:00, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 1134
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 26340000 bits/sec, 3254 packets/sec
  5 minute output rate 26607000 bits/sec, 3289 packets/sec
     8974430609 packets input, 9809117899373 bytes, 0 no buffer
     Received 1803510 broadcasts (1601913 multicasts)
     0 runts, 1809976 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 1601913 multicast, 0 pause input
     0 input packets with dribble condition detected
     8508259561 packets output, 8135592732093 bytes, 0 underruns
     0 output errors, 0 collisions, 1 interface resets
     0 babbles, 0 late collision, 0 deferred
     0 lost carrier, 0 no carrier, 0 PAUSE output
     0 output buffer failures, 0 output buffers swapped out
2960g#

2960g#show interfaces GigabitEthernet0/5
GigabitEthernet0/5 is up, line protocol is up (connected)
  Hardware is Gigabit Ethernet, address is 0022.bd38.b485 (bia 0022.bd38.b485)
  Description: proxmox-node-1
  MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
     reliability 255/255, txload 6/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive set (10 sec)
  Full-duplex, 1000Mb/s, media type is 10/100/1000BaseTX
  input flow-control is off, output flow-control is unsupported
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:00:04, output 00:00:00, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 249
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 897000 bits/sec, 1193 packets/sec
  5 minute output rate 25555000 bits/sec, 2168 packets/sec
     4569823856 packets input, 2655578181223 bytes, 0 no buffer
     Received 1005668 broadcasts (604305 multicasts)
     17 runts, 0 giants, 0 throttles
     17 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 604305 multicast, 4171 pause input
     0 input packets with dribble condition detected
     6100296857 packets output, 7939546009895 bytes, 0 underruns
     0 output errors, 0 collisions, 1 interface resets
     0 babbles, 0 late collision, 0 deferred
     0 lost carrier, 0 no carrier, 0 PAUSE output
     0 output buffer failures, 0 output buffers swapped out
2960g#

You can see the counters, broadcasts and multicast. The following picture says exactly the same thing:

(Https://i.postimg.cc/d3yJQ8hL/Cisco-2960-G-Gigabit-Ethernet0-1.jpg)

(Https://i.postimg.cc/wBwqwxKT/Cisco-2960-G-Gigabit-Ethernet0-3.jpg)

(Https://i.postimg.cc/LX7HMy6c/Cisco-2960-G-Gigabit-Ethernet0-4.jpg)

(Https://i.postimg.cc/mDhbJxR3/Cisco-2960-G-Gigabit-Ethernet0-5.jpg)

We haven't said anything about IGMP on the Cisco switch, but there is no corresponding configuration. I mean, the configuration is done with the default settings.

2960g#show ip igmp snooping
Global IGMP Snooping configuration:
-------------------------------------------
IGMP snooping                : Enabled
IGMPv3 snooping (minimal)    : Enabled
Report suppression           : Enabled
TCN solicit query            : Disabled
TCN flood query count        : 2
Robustness variable          : 2
Last member query count      : 2
Last member query interval   : 1000

Vlan 1:
--------
IGMP snooping                       : Enabled
IGMPv2 immediate leave              : Disabled
Multicast router learning mode      : pim-dvmrp
CGMP interoperability mode          : IGMP_ONLY
Robustness variable                 : 2
Last member query count             : 2
Last member query interval          : 1000

Vlan 2:
--------
IGMP snooping                       : Enabled
IGMPv2 immediate leave              : Disabled
Multicast router learning mode      : pim-dvmrp
CGMP interoperability mode          : IGMP_ONLY
Robustness variable                 : 2
Last member query count             : 2
Last member query interval          : 1000

So on, so on for all vlans and interfaces.
There is no IGMP query configured, no filters, just nothing.

With regard to the articles I read on the Internet, since VLAN snooping is activated, the VLAN flow only has to be restricted to its VLAN (broadcast domain). Why do I see all these broadcast multicasts on the AP surface? No such vlan is configured for the pass.
The same applies to the QNAP port. Even if the QNAP port is in access mode, it doesn't care about VLAN at all.
Maybe I missed a few basic things, but I'm not a network type, I just like to play with networks and servers.

Any help / advice is appreciated.
Thank you very much.

Multicast – Manycast servers are not used (receive: AM_MANYCAST drop: bad auth || (NOPEER | NOTRUST))

I created an NTP configuration for SLES12 SP4 (ntp-4.2.8p13) in which only selected interface addresses are used, and I tried to discover Statum 1 and Startum 2 servers using Manycast (ACST) on our intranet. Unfortunately, no servers are added even though they respond to the multicast requests.

The (essential) configuration looks like this:

# Only listen to official interfaces
interface ignore all
interface listen lo
#"interface listen bond0" would listen on aliases like "bond0:a01", too
interface listen 172.20.1.2
# Local stratum-1 servers
restrict 172.20.2.0 mask 255.255.255.0 nomodify notrap version
# Clients from our subnet are allowed as peers
restrict 172.20.1.0 mask 255.255.255.0 nomodify notrap version
# Allow the rest to query the server
restrict 0.0.0.0 mask 0.0.0.0 nomodify noquery nopeer notrap kod limited

keys /etc/ntp.keys      # path for keys file
trustedkey 16 41 42 43 411 421  # define trusted keys
requestkey 16           # key (7) for accessing server variables
controlkey 16           # key (6) for accessing server variables

tos minclock 6 minsane 4
ttl 1 2 3
manycastserver 239.192.123.12 key 421 ttl 3
manycastclient 239.192.123.11 key 41 iburst burst minpoll 5 maxpoll 9 ttl 3
manycastclient 239.192.123.12 key 421 iburst burst minpoll 6 maxpoll 11 ttl 3

I don't know if the problem is due to the set up of my restrictions or the use of a key with manycast client:
It appears that the answers lack a MAC.

Query sent:

poll_update: at 2 239.192.123.11 poll 5 burst 0 retry 0 head 0 early 2 next 33
    MCAST   ***** sendpkt(19, dst=239.192.123.11, src=172.20.1.2, ttl=3, len=48)

Receive package:

receive: at 3 239.192.123.12<-172.20.1.2 ippeerlimit -4 mode 3 iflags mcastopen,MCASTif restrict ignore org 0000000000.00000000 xmt 0xe1b478bb.63e6cc7f
receive: drop: RES_IGNORE

The manycast packets seem to be ignored:

receive: at 3 172.20.1.2<-172.20.1.1 mode 4/server:AM_MANYCAST len 48 org 0xe1b478bb.63e6cc7f xmt 0xe1b478bb.63e8507e NOMAC
receive: MATCH_ASSOC dispatch: mode 4/server:AM_MANYCAST 
receive: AM_MANYCAST drop: bad auth || (NOPEER|DONTTRUST)

I suspect this NOMAC be the problem.
How can I achieve this or is it a software error?

Networking – Why does my multicast not work between two PCs?

I work with multicast and stream a file 224.0.0.149 IP. With my PC I can listen to the stream with the VLC client. But if I try to receive from another PC with the same router, I can not reach the stream. Although the router is configured with multicast. I also checked my network interfaces for multicast IPs netsh interface ip show joins Command. Most of them are:

224.0.0.1
224.0.0.251
224.0.0.252
239.255.255.250

Is it possible to create a multicast IP? 224.0.0.149 to my network interface?

Router IGMP is also enabled for multicast.

Enter image description here

Linux – Generating multicast MAC frames through a tunnel

I want to transmit / tunnel complete UDP IPv4 packets over a non-standard interface that uses its own L2 framing (we do not transport the Ethernet frame header). On the receiver side, I want to generate a new Ethernet frame header that has set multicast, unicast, and broadcast destination addresses accordingly. Embedded devices will run Linux Kernel 4.9 and its embedded software.

(PC 0) -eth-> ( embed dev 0 ) -other-> ( embed dev 1 ) -eth-> (PC 1)

  1. Capture the complete UDP IPv4 packet from the eth0 of embed dev 0 (addressed to each; promiscuous mode; strip ethernet frame headers)
  2. Transport the package between embedded devices (no problems here)
  3. Place the complete UDP IPv4 packet to embed the eth0 of dev 1 (original source and destination IPv4 addresses are present).
    1. embed dev 1 & # 39; s eth0 should generate a matching MAC Destination Address (Unicast, Multicast, Broadcast)

Problems / questions about each list number:

  1. I can capture frames easily by creating a Tap device and overriding it with eth0. How do I collect full UDP packets? Based on what I have seen so far with libpcap, this seems to be the only way …

  2. No problem

  3. I think the correct way to do that is to create a socket in IPPROTO_RAW mode (make sure IP_HDRINCL is set). If this is done, is the L2-MAC destination address generated correctly?

Am I doing this all wrong and should I do something with the tuntap driver instead? Any hints would be greatly appreciated or if more information would be useful. Thank you very much.

Linux – Sophos UTM 9 OSPF HI messages are not multicast

I am trying to enable OSPF on a Sophos UTM 9 on a LAN interface on which two other routers successfully run OSPF.

My configuration is as follows.

Interfaces and Routing -> Dynamic Routing (OSPF)

  • Area
    • Name: normal 0.0.0.0
    • Domain ID: 0.0.0.0
    • Surface type: Normal
    • Auth Type: Off
    • Connection via interface: LAN1
  • interfaces
    • Name: LAN1
    • Interface: LAN1
    • Auth Type: Off
    • Cost: 0
    • Advanced
      • Hello interval: 10
      • Retransmission interval: 5
      • Dead time: 40
      • Priority: 1
      • Transmission delay: 1
    • Advanced
      • Redistribute connected <- Enabled
      • Metric: 10
    • Global
      • OSPF status: switched on (ie green)
      • Router ID: 192.168.30.1 (ie the IP address on the LAN1 interface)

The firewall configuration looks like this to allow OSPF multicast messages:

Network protection -> Firewall

  • LAN1 —– (OSPF) —–> Multicast
  • Multicast —– (OSPF) —–> LAN1

Here, OSPF is defined as a service definition with the following characteristics:

  • Name: OSPF
  • Type of definition: IP
  • Protocol number: 89

Multicast is defined here as a network definition with the following characteristics:

  • 224.0.0.0/4
  • Interface: Any

When I log in to Sophos UTM 9 as root and run tcpdump on the LAN1 interface, OSPFv2 hello messages are sent from the directly connected router to the multicast address 224.0.0.5, but Sophos UTM 9 does not send any OSPF "hello" messages ,

One thing struck me … It seems that enabling OSPF on the interface in question does not subscribe to this interface for the relevant OSPF multicast groups: 224.0.0.5 and 224.0.0.6

This should not affect outgoing Multicast OSPF messages (here, as already mentioned, I see the problem).

To the incoming Messages, as stated above, tcpdump shows that they hit the network card, but I doubt they will forward the TCP / IP stack due to the lack of a subscription.

my-utm:/root # ip maddr show eth0
2: eth0
link 33:33:00:00:00:01
link 33:33:00:00:00:02 users 2
link 01:00:5e:00:00:01
inet 224.0.0.1
inet6 ff05::2
inet6 ff01::2
inet6 ff02::2
inet6 ff02::1
inet6 ff01::1

Can someone see from the configuration and observations described above what I am doing wrong?

Thank you in advance.

wireless – Collect multicast packets in the WLAN

That depends on the package being encrypted. If you capture a multicast packet sent over an open Wi-Fi network, you can read it easily.

If the package is encrypted, you will need the key to successfully read the package.

The reason why you can generally use multicast is because of the OSI layer model. For the higher layers, it simply does not matter how the lower layers are implemented. If a network uses mixed clients (some wired, some wireless), multicast and broadcast must continue to work.

netstat – Configuration of two interfaces with different gateways via routes (for multicast purposes)

I really need some help.

I want to configure two different interfaces, one for the Internet and one for multicast (which I need for UDP multicast streams).

What I have done so far: netstat configuration

eno1 is the interface that I want to use for multicast purposes, eno2 is the one for the internet. I have tried the other way, but no success.

The problem is that I can not stream udp multicast, for example: udp: //@227.10.10.66: 12345 does not work. I doubt it has anything to do with routes and gateways. When I ping the multicast interface gateway 172.17.185.254, it works. When I removed the configuration of the internet interface and the internet LAN cable, the other interface (multicast interface) worked.

What do you suggest to me? Thank you in advance for those who take the time to read this at least.

unreal 4 – How do I create a multicast delegate in Blueprint?

I used the Timer by Event set, but I could not use the delegate in more than one event:

Enter image description here

I've researched and it's possible, but I only found results in c ++:

https://docs.unrealengine.com/en-US/Programming/UnrealArchitecture/Delegates/index.html

My code:

Enter image description here

This is not functional at all. I use the same function twice.

I could call the "second" event after running the "first" event, but would like to know how to use the delegate (if any) in multiple events.