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A Glorious Hack

Today, a buddy mentioned that his blog wasn’t loading. His blog was hosted on one of the servers behind silverfir.net, minimus. It’s the one with the really interesting setup: Windows Server running Ubuntu Linux in a VM.

I luckily remembers how to log into the Windows server via remote desktop and poking around I discovered that something had gone wonky with the VM image. A reboot + disk scan didn’t fix the issue, so I created a new VM image and mounted the same disk images and things seems to start working reasonably well again.

Except that the port forwarding wasn’t working. Minimus is NAT’ed behind a very high-speed residential line, and the dd-wrt router it’s behind forwards a few relevant ports to the right place: 22 and 80 come to mind. Somehow, perhaps because of a new (virtual) MAC address, the forwarding wasn’t working any more.

I wanted to get the sites back online, but I didn’t have access to the router’s admin interface, so I came up with a glorious hack. Here’s what I did:

(1) ssh with port forwarding from minimus to nexus to forward port 5050 on nexus to port 80 on minimus: ssh -R 5050:localhost:80 nexus.silverfir.net
(2) on nexus, create an nginx config that forwards all the relevant sites to port 5050
(3) point the dns entries for all the relevant sites to nexus instead of minimus

It is working surprisingly well, but of course this is a super fragile state where one connection dropping will mean all the sites become unavailable again. If you care much about content hosted on minimus, you should probably take this chance to back it up.

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