[READ-ONLY] Mirror of https://github.com/FoxxMD/blog.
blog.foxxmd.dev
Add more info on disabling 121 for target marchine
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_drafts/netbird-and-docker.md
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_drafts/netbird-and-docker.md
···
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Can use [DHCPCD or DHCLIENT hooks](https://netbeez.net/blog/linux-dhcp-hooks-network-engineers/) to setup a script to delete the route when the associated interface comes up:
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```shell
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#!/bin/bash
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if [[ "$interface" == "ensX" ]]
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if [ "$interface" == "ensX" ]
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then
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echo -e "\nRemoving extra routes"
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ip route del 100.110.0.0/16 via 192.168.0.X dev ensX
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fi
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```
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Or try running after interface is up with systemd
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```
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[Unit]
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Description=Drop static route
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After=ifup@ens18.service
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[Service]
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# the - forces systemd to ignore error from command if route doesn't exist
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ExecStart=-ip route del 100.110.0.0/16 via 192.168.0.X dev ens18
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[Install]
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WantedBy=multi-user.target
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```
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Neither of the above ended up working for me...the route seems to be added *after* the interface is up but I can't figure out where in the system boot up lifecycle.
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The only thing did work for me was disabling *all* dhcp option 121 functionality by editing `dhclient` config and commenting out this line:
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```diff
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-option rfc3442-classless-static-routes code 121 = array of unsigned integer 8;
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+#option rfc3442-classless-static-routes code 121 = array of unsigned integer 8;
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```
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{: file='/etc/dhcp/dhclient.conf'}
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This is not ideal but it works, for now.
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## Test Routing
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