<div dir="ltr">Hey Drew,<div><br></div><div>This is what I meant about conmon being built-in. You can chain connectivity-monitoring for monitoring, have it syslog, and then react to the syslog using an event handler. Gives you a lot of flexibility.</div><div><br></div><div>Something like this, where 10.0.0.1 is reachable on local interface via L2 transport, so we monitor it. Then depending on if it's up or not, we add or remove a static route to <a href="http://10.1.2.3/32">10.1.2.3/32</a> toward 10.0.0.1.</div><div><br></div><div>monitor connectivity</div><div> no shutdown</div><div> !<br> host host1<br> ip 10.0.0.1</div><div><br></div><div>--- Syslog output:</div><div>
<p class="gmail-p1" style="margin:0px;font-style:normal;font-variant:normal;font-size-adjust:none;font-kerning:auto;font-feature-settings:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures">2026-09-11T11:54:31.144742-07:00 LAB-MGMT-48ZC2 ConnectivityMonitor: %CONNECTIVITYMON-5-HOST_UNREACHABLE: Host host1 (10.0.0.1) is unreachable with ICMP probes</span></p><p class="gmail-p1" style="margin:0px;font-style:normal;font-variant:normal;font-size-adjust:none;font-kerning:auto;font-feature-settings:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures">
</span></p><p class="gmail-p1" style="margin:0px;font-style:normal;font-variant:normal;font-size-adjust:none;font-kerning:auto;font-feature-settings:normal;font-stretch:normal;font-size:11px;line-height:normal;font-family:Menlo;color:rgb(0,0,0)"><span class="gmail-s1" style="font-variant-ligatures:no-common-ligatures">2026-09-11T11:58:67.530900-07:00 LAB-MGMT-48ZC2 ConnectivityMonitor: %CONNECTIVITYMON-5-HOST_REACHABLE: Host host1 (10.0.0.1) is reachable with ICMP probes</span></p></div><div><br></div><div>--- Built event-handler:</div><div>event-handler Host1Down<br> action bash Cli -p15 -c $'enable\n configure\n no ip route <a href="http://10.1.2.3/32">10.1.2.3/32</a> 10.0.0.1\n end'<br> delay 0<br> asynchronous<br> !<br> trigger on-logging<br> regex "Host host1 .* is unreachable .*"<br></div><div><br></div><div>event-handler Host1Up<br> action bash Cli -p15 -c $'enable\n configure\n ip route <a href="http://10.1.2.3/32">10.1.2.3/32</a> 10.0.0.1\n end'<br> delay 0<br> asynchronous<br> !<br> trigger on-logging<br> regex "Host host1 .* is reachable .*"</div><div><br></div><div>Is this what you're after?</div><div><br></div><div>-T</div></div><br><div class="gmail_quote gmail_quote_container"><div dir="ltr" class="gmail_attr">On Fri, Sep 11, 2026 at 12:36\u202fPM Drew Weaver <<a href="mailto:drew.weaver@thenap.com">drew.weaver@thenap.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div class="msg4680710327455908971">
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<p class="MsoNormal"><span style="font-size:11pt">Right but none of that is built into EOS correct?<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11pt"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11pt">That was what the post was mostly about.<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11pt"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11pt">Whether they had ever gone back and corrected the omission?<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11pt"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11pt">Thanks,<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11pt">-Drew<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11pt"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11pt"><u></u> <u></u></span></p>
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<p class="MsoNormal"><b><span style="font-size:11pt;font-family:Calibri,sans-serif">From:</span></b><span style="font-size:11pt;font-family:Calibri,sans-serif"> Tyler Conrad <<a href="mailto:Tyler@tgconrad.com" target="_blank">Tyler@tgconrad.com</a>>
<br>
<b>Sent:</b> Friday, September 11, 2026 1:25 PM<br>
<b>To:</b> Drew Weaver <<a href="mailto:drew.weaver@thenap.com" target="_blank">drew.weaver@thenap.com</a>><br>
<b>Cc:</b> <a href="mailto:arista-nsp@puck.nether.net" target="_blank">arista-nsp@puck.nether.net</a><br>
<b>Subject:</b> Re: [a-nsp] tracked static routes in EOS<u></u><u></u></span></p>
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<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">Hi Drew,<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">I've worked on a couple extensions to do this over the years, and there's also a built-in way.<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">Built-in: Connectivity-monitor with an on-logging event-handler can work for script-less behavior.<u></u><u></u></p>
<p class="MsoNormal">PingCheck Extension: <a href="https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_arista-2Deosext_PingCheck&d=DwMFaQ&c=euGZstcaTDllvimEN8b7jXrwqOf-v5A_CdpgnVfiiMM&r=OPufM5oSy-PFpzfoijO_w76wskMALE1o4LtA3tMGmuw&m=bPv27DsWHvJOKXO1fg-IGUnqlmv3IzCXU57K_UK6OKd83rMtLkgFxTjUGCICVrCw&s=U1Lbsb6ispBFDPisCYWxAwXksSBjf3cioxLYf8pn-ro&e=" target="_blank">https://github.com/arista-eosext/PingCheck</a>
- this one uses a simple ping check.<u></u><u></u></p>
<p class="MsoNormal">SynAcktor Extension: <a href="https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_etedor_synacktor&d=DwMFaQ&c=euGZstcaTDllvimEN8b7jXrwqOf-v5A_CdpgnVfiiMM&r=OPufM5oSy-PFpzfoijO_w76wskMALE1o4LtA3tMGmuw&m=bPv27DsWHvJOKXO1fg-IGUnqlmv3IzCXU57K_UK6OKd83rMtLkgFxTjUGCICVrCw&s=49RFYRbP_3OyShNE6hz-8Ix9XOqpCVFYwaU7o1C8Uc8&e=" target="_blank">https://github.com/etedor/synacktor</a>
- adds flexibility to be able to monitor a tcp service and set an arbitrary next-hop. Useful for monitoring a path without changing the routing table.<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">Hope this helps,<u></u><u></u></p>
<p class="MsoNormal">-T<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">On Fri, Sep 11, 2026 at 9:03<span style="font-family:Arial,sans-serif">\u202f</span>AM Drew Weaver via arista-nsp <<a href="mailto:arista-nsp@puck.nether.net" target="_blank">arista-nsp@puck.nether.net</a>> wrote:<u></u><u></u></p>
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<p class="MsoNormal"><span style="font-size:11pt">Howdy</span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:11pt"> </span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:11pt">Is it true that there really is no way to do tracked static routes in EOS without installing a python script that you have to reinstall every time
the switch reboots?</span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:11pt"> </span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:11pt">By tracked static routes I just mean a route that withdrawals when something stops pinging (or another tracking mechanism) would just use BFD but
the device on the far end of the L2 network doesn\u2019t support it.</span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:11pt"> </span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:11pt">Use case is basically just a L2 network in between the route origin and the destination. if the entire network goes down and the physical link facing
the route originating device disappears then the route is withdrawn anyway but if only the portion on the other side of the L2 network goes down then you\u2019re null routing traffic unintentionally.</span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:11pt"> </span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:11pt">I\u2019m just wondering.</span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:11pt"> </span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:11pt">Thanks,</span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:11pt">-Drew</span><u></u><u></u></p>
<p class="MsoNormal"><span style="font-size:11pt"> </span><u></u><u></u></p>
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<p class="MsoNormal">-- <br>
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