The command
ssh root@openwrt "tcpdump -i lan0 -U -w -" | wireshark -k -i -
as described here:
https://openwrt.org/docs/guide-user/firewall/misc/tcpdump_wireshark
allows viewing of network traffic on the OpenWrt host from another host. The command works, but when Wireshark is closed the pipe stalls and the tcpdump command must be killed manually.
This is using OpenWrt 24.10.2 with Dropbear server v2024.86 and an OpenSSH client.
A minimal test case is:
ssh user@host "cat /dev/zero" |false
as described here:
https://unix.stackexchange.com/questions/161690/terminating-ssh-called-from-a-script-sigpipe-handling
The command hangs when connecting to OpenWrt running Dropbear, but terminates normally when connecting to a server running OpenSSH.
I've also reproduced the problem by running the test case against an Ubuntu machine which has the dropbear package installed, running Dropbear server version 2022.83-4. Again, if OpenSSH server version 9.9 is installed instead, the test command terminates normally.
The command
ssh root@openwrt "tcpdump -i lan0 -U -w -" | wireshark -k -i -as described here:
https://openwrt.org/docs/guide-user/firewall/misc/tcpdump_wireshark
allows viewing of network traffic on the OpenWrt host from another host. The command works, but when Wireshark is closed the pipe stalls and the tcpdump command must be killed manually.
This is using OpenWrt 24.10.2 with Dropbear server v2024.86 and an OpenSSH client.
A minimal test case is:
ssh user@host "cat /dev/zero" |falseas described here:
https://unix.stackexchange.com/questions/161690/terminating-ssh-called-from-a-script-sigpipe-handling
The command hangs when connecting to OpenWrt running Dropbear, but terminates normally when connecting to a server running OpenSSH.
I've also reproduced the problem by running the test case against an Ubuntu machine which has the dropbear package installed, running Dropbear server version 2022.83-4. Again, if OpenSSH server version 9.9 is installed instead, the test command terminates normally.