다른 시스템의 ping을 통해 가상 인터페이스에 접근할 수 없습니다.

직접 링크를 통해 두 개의 Debian 10 시스템이 연결되어 있습니다.

그 중 하나에서는 가상 인터페이스를 정의했고 다른 하나에서는 이에 액세스하기 위한 정적 경로를 제공했습니다. 인터페이스에는 보낸 사람의 트래픽이 표시되지만 상대방 시스템에는 트래픽이 표시되지 않고 응답도 수신되지 않습니다.

상대방의 시스템에 의해 트래픽이 중단되었을 가능성이 있습니까?

sudo ip link add lo1 type dummy
sudo ip link set dev lo1 up
sudo ip addr add 13.13.13.13/32 dev lo1

pc2~$ ip addr show lo1
   63: lo1: <BROADCAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default qlen 1000
    link/ether ae:e2:d8:95:2b:ae brd ff:ff:ff:ff:ff:ff
    inet 13.13.13.13/32 brd 13.13.13.13 scope global lo1
       valid_lft forever preferred_lft forever
    inet6 fe80::ace2:d8ff:fe95:2bae/64 scope link 
       valid_lft forever preferred_lft forever


pc2~$ sudo sysctl -p
sysctl: cannot stat /proc/sys/net/ipv4/tcp_syncookies: No such file or directory
net.ipv4.conf.all.log_martians = 1
net.ipv4.conf.all.accept_redirects = 0
net.ipv4.conf.all.accept_source_route = 0
net.ipv4.icmp_echo_ignore_broadcasts = 1
kernel.printk = 1 4 1 7
net.ipv4.conf.all.rp_filter = 2
net.ipv4.conf.all.arp_ignore = 1
net.ipv4.conf.all.arp_announce = 2

그리고 또 다른 시스템:

sudo ip route add 13.13.13.13/32 via 20.20.20.2

pc1~$ ip addr show port25
31: port25: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 04:f8:f8:76:53:59 brd ff:ff:ff:ff:ff:ff
    inet 20.20.20.1/24 brd 20.20.20.255 scope global port25
       valid_lft forever preferred_lft forever
    inet6 fe80::6f8:f8ff:fe76:5359/64 scope link 
       valid_lft forever preferred_lft forever

pc1(20.20.20.1)---------(20.20.20.2)pc2(lo2:13.13.13.13/32)

pc1~$ sudo tcpdump -ni port25 icmp

We trust you have received the usual lecture from the local System
Administrator. It usually boils down to these three things:

tcpdump: verbose output suppressed, use -v[v]... for full protocol decode
listening on port25, link-type EN10MB (Ethernet), snapshot length 262144 bytes




22:54:42.098033 IP 20.20.20.1 > 13.13.13.13: ICMP echo request, id 3321, seq 0, length 64
22:54:43.107142 IP 20.20.20.1 > 13.13.13.13: ICMP echo request, id 3321, seq 1, length 64
22:54:44.117137 IP 20.20.20.1 > 13.13.13.13: ICMP echo request, id 3321, seq 2, length 64
22:54:45.127138 IP 20.20.20.1 > 13.13.13.13: ICMP echo request, id 3321, seq 3, length 64
22:54:46.137143 IP 20.20.20.1 > 13.13.13.13: ICMP echo request, id 3321, seq 4, length 64

pc2:~$ sudo tcpdump -ni port25 icmp
Password: 
tcpdump: verbose output suppressed, use -v[v]... for full protocol decode
listening on port25, link-type EN10MB (Ethernet), snapshot length 262144 bytes

pc1~$ ip route
default nhid 16 via 192.168.60.2 dev enp0 proto 196 metric 20 
13.13.13.13 nhid 79 via 20.20.20.2 dev port25 proto 196 metric 20 
20.20.20.0/24 dev port25 proto kernel scope link src 20.20.20.1 
50.50.60.60 nhid 16 via 192.168.60.2 dev enp0 proto 196 metric 20 
192.168.60.0/24 dev enp0 proto kernel scope link src 192.168.60.75 
192.168.121.0/24 dev port2 proto kernel scope link src 192.168.121.37 linkdown 

pc2~$ ip route
default nhid 26 via 192.168.60.2 dev enp0 proto 196 metric 20 
20.20.20.0/24 dev port25 proto kernel scope link src 20.20.20.2 
192.168.22.0/24 dev port1 proto kernel scope link src 192.168.22.156 
192.168.60.0/24 dev enp0 proto kernel scope link src 192.168.60.76 
zharf-switch:~$