Serving Web from volatile Dial-up IP

# Serving Web from volatile Dial-up IP Source: [https://blog.mro.name/2026/09/web-from-dial-up/](https://blog.mro.name/2026/09/web-from-dial-up/) My homelab is behind a dial\-up IP link with occasional unexpected reconnects\. There is dynamic DNS, but I prefer a reverse proxy[\[1\]](https://blog.mro.name/2026/09/web-from-dial-up/#fn:prx)between the bots and me\. And dyndns doesn't notify other servers \(the reverse proxy\)\. ## No push? Then poll\. There's a cron\-job on the homelab server triggering a refresh of the reverse proxy cfg if the IP has changed: ``` # note: no sudo $ crontab -l */15 * * * * .local/bin/http-up.sh snac.mro.name vps.mro.name /var/www/vhosts/snac.mro.name/proxy-dyndns.conf ``` with a \(local\) script doing the heavy lifting \(shell escaping mostly\): ``` #!/bin/sh [ "$3" = "" ] && { cat <<EOFz Check if localhost can curl an url and if not, envsubst the current IP as \$IPv4 into a (remote) reverse proxy config in case & reload (lighttpd). SYNOPSIS \$ $0 <http url> <ssh host> <reverse proxy cfg file> EOFz exit 0 } curl \ --fail \ --location \ --max-time 3.1 \ --output /dev/null \ --silent \ "$1" \ && exit 0 ssh -4 "$2" \ "IPv4=\$(echo \$SSH_CLIENT | cut -d ' ' -f 1) envsubst \ < \"$3.tpl\" \ > \"$3\" sudo service lighttpd reload ls -l \"$3\" " ``` After DSL reconnects, the server comes back online with the new IP within the next 15 minutes \- fine for me\. No other parties involved and the volatile host notifies the passive reverse proxy\. And: I can make do with cron & ssh and need no other tools or services\.