Adding default routes in dhclient-exit-hooks breaks ssh until first sending a ping

Tobias Nilsson

9/1/24, 6:52 AM

I nave a system running with 2 network cards. To make sure the default route is correct for each card added the following to /etc/dhclient-exit-hooks:

if [[ "$interface" == "eth0" ]]; then
    if [ "$reason"  == "BOUND" ]; then
        ip rule add from "$new_ip_address" table 234
        ip route add default via "$new_dhcp_server_identifier" dev "$interface" table 234
        fi
fi

if [[ "$interface" == "eth1" ]]; then
    if [[ "$reason"  == "BOUND" ]]; then
        ip rule add from "$new_ip_address" table 345
        ip route add default via "$new_dhcp_server_identifier" dev "$interface" table 345
    fi
fi

Now to the issue when i try and ssh into the system is says that there is no route to host. But if i first ping the system and then try and ssh it works. What am I doing wrong here?

0 + 1

ssh

dhcp

Raffa

9/1/24, 8:06 AM

for `dhclient`, you probably need to place your executable script under `/etc/dhcp/dhclient-exit-hooks.d/` and not under `/etc/` ... And the need to ping first to update the external network equipment tables/routes indicates a non-optimal network configuration.

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: Adding default routes in dhclient-exit-hooks breaks ssh until first sending a ping

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