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  • 1.  OSPF neighborship stuck in INIT due to hello packet size

    Posted 05-09-2022 11:32
    Has anyone else noticed an issue on SRX devices where the hello packets are sometimes 56 bytes instead of 60? Here is a tcpdump:

    11:20:05.549433  In IP 192.168.216.29 > 224.0.0.5: OSPFv2, Hello, length 56
    11:20:05.767757 Out IP 192.168.215.30 > 224.0.0.5: OSPFv2, Hello, length 60
    11:20:06.384321  In IP 192.168.216.29 > 224.0.0.5: OSPFv2, Hello, length 56
    11:20:06.586991 Out IP 192.168.215.30 > 224.0.0.5: OSPFv2, Hello, length 60
    11:20:07.324418  In IP 192.168.216.29 > 224.0.0.5: OSPFv2, Hello, length 56
    11:20:07.574520 Out IP 192.168.215.30 > 224.0.0.5: OSPFv2, Hello, length 60​

    I have seen this in my environment many times. I have seen this on 19.2r2.7 and 21.3r1. SRX models 300 and 380. Both in cluster mode and standalone. Is this a known bug? Would love to see information on this issue and possible resolution steps.

    On one SRX I was able to reboot the device which fixed the issue. The neighborship was in FULL state and when I ran a tcpdump, the inbound Hello packets showed length 60. But on another SRX, rebooting did not work and we still aren't sure how to fix this.

    ------------------------------
    CHRISTIAN DE LA PENA
    ------------------------------


  • 2.  RE: OSPF neighborship stuck in INIT due to hello packet size

    This message was posted by a user wishing to remain anonymous
    Posted 05-10-2022 11:27
    This message was posted by a user wishing to remain anonymous

    write a pcap to a file, download to your pc and then decode it with wireshark to see what is the difference.

    see below example:

    lab@router> monitor traffic interface xe-0/0/1 write-file /var/tmp/ospf.pcap matching "proto 89" size 512 count 5
    Address resolution is ON. Use <no-resolve> to avoid any reverse lookup delay.
    Address resolution timeout is 4s.
    Listening on xe-0/0/1, capture size 512 bytes


    lab@router>

    lab@router> file list /var/tmp/ospf.pcap detail
    -rw-r--r-- 1 lab wheel 654 May 10 04:51 /var/tmp/ospf.pcap
    total files: 1


  • 3.  RE: OSPF neighborship stuck in INIT due to hello packet size

     
    Posted 05-11-2022 09:44
    Pure speculation, but given the difference being 4 bytes, my guess is that it is most likely related to VLAN tagging on the interface. In this case I notice that the ingressing packet is 56 bytes while it's the egressing packet that is 60 bytes. Your best bet would be to do a packet capture like the other suggestion in this thread and compare the packets.