Select Your Language

Infrastructure and Management

Cloud Computing

Storage

Runtimes

Integration and Automation

  • Comments
  • ICMP replies captured but not considered by ping

    Posted on

    On my server, I configured 3 IP in the same network (172.16.26.10/27) :
    bond0 : 172.16.26.10
    eth3 : 172.16.26.27
    eth5 : 172.16.26.26
    The gateway is in this network 172.16.26.6 but

    I can ping this gateway from bond0 interface but not from eth3 neither eth5. All packet are seen as lost

    [root@admin0 ~]# ping -I eth3 172.16.26.6
    PING 172.16.26.6 (172.16.26.6) from 172.16.26.27 eth3: 56(84) bytes of data.
    ^C
    --- 172.16.26.6 ping statistics ---
    7 packets transmitted, 0 received, 100% packet loss, time 6582ms

    However, when I capture icmp traffic during the ping I can see that requests and replies.

    [root@admin0 ~]# tcpdump -r /tmp/ping_router_from_eth3_2.pcap | grep -i icmp
    reading from file /tmp/ping_router_from_eth3_2.pcap, link-type EN10MB (Ethernet)
    17:03:19.775411 IP admin0-sig-sec > 172.16.26.6: ICMP echo request, id 48904, seq 1, length 64
    17:03:19.775523 IP 172.16.26.6 > admin0-sig-sec: ICMP echo reply, id 48904, seq 1, length 64
    17:03:20.775312 IP admin0-sig-sec > 172.16.26.6: ICMP echo request, id 48904, seq 2, length 64
    17:03:20.775429 IP 172.16.26.6 > admin0-sig-sec: ICMP echo reply, id 48904, seq 2, length 64
    17:03:21.775306 IP admin0-sig-sec > 172.16.26.6: ICMP echo request, id 48904, seq 3, length 64
    17:03:21.775437 IP 172.16.26.6 > admin0-sig-sec: ICMP echo reply, id 48904, seq 3, length 64
    17:03:22.775147 IP admin0-sig-sec > 172.16.26.6: ICMP echo request, id 48904, seq 4, length 64
    17:03:22.775277 IP 172.16.26.6 > admin0-sig-sec: ICMP echo reply, id 48904, seq 4, length 64
    17:03:23.774346 IP admin0-sig-sec > 172.16.26.6: ICMP echo request, id 48904, seq 5, length 64
    17:03:23.774477 IP 172.16.26.6 > admin0-sig-sec: ICMP echo reply, id 48904, seq 5, length 64
    17:03:24.774290 IP admin0-sig-sec > 172.16.26.6: ICMP echo request, id 48904, seq 6, length 64
    17:03:24.774415 IP 172.16.26.6 > admin0-sig-sec: ICMP echo reply, id 48904, seq 6, length 64
    17:03:25.774316 IP admin0-sig-sec > 172.16.26.6: ICMP echo request, id 48904, seq 7, length 64
    17:03:25.774421 IP 172.16.26.6 > admin0-sig-sec: ICMP echo reply, id 48904, seq 7, length 64
    tcpdump: pcap_loop: truncated dump file; tried to read 66 captured bytes, only got 21

    Why ping command considered packet as lost whereas I can capture the reply ?

    by

    points

    Responses

    Red Hat LinkedIn YouTube Facebook X, formerly Twitter

    Quick Links

    Help

    Site Info

    Related Sites

    © 2026 Red Hat