Category Archives: networking

SSH Certificate signing

I’ve encountered a problem migrating from Fedora to Arch which ends up being about ssh and openssh certificates. I look back and discover that I never posted anything about my movement toward openssh certificates. Curious because I wrote a lengthy document about it (because of my leaky brain – not because I am any kind of authority on it).

I will probably go back and write a post about it, and back date it. But now a problem has arisen. Rather than explain, let the boys at openssh speak for themselves, in the release notes for openssh 8.2:

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Moving Oregano to arch

It is by no means certain that I will succeed with this effort, but I’m spending some time trying to get Oregano up on Arch.

The first step was just to get Arch booted up on oregano. My previous installation on a laptop didn’t involve an encrypted root, didn’t have raid arrays, didn’t have separate filesystems for things like /home and /var, didn’t run a web server, etc., so the first challenge is to get the system up with all that stuff.

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Apache certificate chains

When I switched my main server to CentOS, described in an earlier post, one of the big pains was that I had to use CentOS 7, and there was a lot of software which had come a long way since CentOS 7, and I had to upgrade a log of things from upstream to get functionality that I had grown reliant upon.

I didn’t realize that Apache itself was one of those things that was sufficiently backwards in CentOS 7 that I would have trouble.

Ever since I move the server to CentOSdid that “upgrade”, I’ve been struggling with problems with the certificates not being honored. For the last few days I have been working pretty diligently to try to figure out this nagging problem, and today I finally figured it out. It is owing to an old Apache.

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Odd VPN Problem

I have had trouble twice now with modifying a working vpn configuration, and then being unable to get it to start. Both times I never actually solved it, so much as eliminating the problem by switching to a different nordvpn config file.

There was a penetration at nordvpn in which some passwords and userinfo were leaked. I wanted to change my password, and did, and had to get into the vpn router and change it there. And after I did the vpn just would not start. Eventually, I switched to another vpn endpoint, put in a new .conf file in /etc/openvpn/client and it came right up.

I don’t know what this is about.

Tarragon Rebuild 2019

This server, on Amazon, hosts my website and a dozen others, provides mail service for several people’s email including my own with postfix, dovecot, opendkim, amavis, spamassassin and clamd, provides contacts and calendar service using radicale, provides vpn service with openvpn, provides a tor relay, provides nextcloud service, and hosts my svn repository.

The server was last rebuilt in 2017. Long, long ago when I built the first version of it, I was most familiar with Red Hat/Fedora, and since then it has been easiest just to upgrade it with Fedora, always grumbling to myself that someday I’m going to change it. The problem with being on Fedora, of course, is that Fedora changes every 6 months, so I’m constantly behind. And after a year I’m at end of life. This is dumb for a server that I don’t want to be messing with all the time.

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Memory on the Gateway Pi

I now have 8 of these gateway boxes out there. This morning as I was checking backups on one of them, I observed that it took quite a long time to respond. I ran a top on it and was horrified to see that its memory use was 100% and so was its swap. Holy @#$%!@ Batman!

Most of the memory was being used by the lxpanel. And (hangs head in embarrassment) there were actually two lxpanels running – one for the console and one in the vnc window I launch at startup.

It seems the lxpanels leak. I don’t know how badly, but it doesn’t matter. These boxes are meant to run forever so even a tiny leak is eventually fatal.

Well this was simple. I will seldom, if ever, need to get into a graphical environment remotely, and if I do I can always start vnc from the command line. So I took out the startvnc from the startup script. And I have even LESS need for a graphical console since there is not even a monitor on these things. So I set the default systemd target to

Did this on all the gateways that are running on pi-zeros. Those few running on bigger ubuntu boxes I didn’t really have the problem anyway.

After rebooting them they come up with no lxpanels. I’ll watch the memory use, but I think this will fix the problem.

Setting up a mac remotely

I want to be able to get to my wife’s mac, in another city. She is an unsophisticated user, and I’d like to be able to help her when she needs help, but I can’t ask her to do very much setup. I also want to be able to provide backup for her files.

The first step was to outfit her with one of the little gateway pis previously described. Once that was done, we managed, together, to enable me to get to her mac with ssh, by way of the pi tunnel. And we managed to set up an account on her mac under my name.

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Gateway pi

I realized as I was writing a new post that I had never documented the gateway pi undertaking.

This started when a friend in the mountains got a new internet service where the ISP would not allow him (and therefore me) access to his router. As a result I could no longer use ssh to connect to his systems.

I solved this problem by setting his systems up to use a tool called autossh, with which I could have his system start, monitor, and keep running an ssh daemon with reverse tunnels open to my system. I could then reach him by attaching through the reverse tunnels.

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Adding a VPN Router to the network

The topology for the handling of downloads of stuff via a vpn previously involved a vpn client directly on rosemary. The problem with this was that sometimes the vpn would fail – it would get disconnected from the remote end. If I didn’t realize this, and started a download, it would be in the clear.

I thought a better solution was to have a separate router (herein the “vpn” router) between rosemary and the external router, and to have that router establish a constant vpn through it’s wan interface, through the external router. Everything that connected to a lan port on the vpn router would be protected. Rosemary would then use the vpn router as its path to the internet. Everything that rosemary sends or receives from the internet would come exclusively through the vpn router.

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New Internal Network setup

Owing to the failure of oregano detailed in the last post, I have finally taken steps to clean up a long standing issue in my internal network, viz: that oregano, the primary development computer was offering essential network services which all the other boxes relied upon. When oregano was down, almost everything else suffered.

This problem dates back at least 20 years. In early days I began the practice of having my primary linux computer act as a firewall separating the rest of the network from the internet, and as the dhcp server. I won’t try to defend the practice – it was what I did; but it has made less and less sense over the years. Plus it had the very undesirable side effect that when that primary computer was down the other systems lost their dhcp server and their path to the net.

I had this generic Chinese openwrt router which I bought last year, for reasons passing understanding. I’d planned to replace the primary router with it, but that proved a bad plan. I decided to use this extra router to fill the role oregano had filled, of separating the internal and external networks.

So this router, named obelisk, performs dhcp and dns forwarding. Henceforth Oregano will be just another box on the internal network.