The Mystery of Path MTU MSS Clamping
I had to get my production server to clamp MSS (size of TCP data “segment” in bytes) to path MTU.
I had to get my production server to clamp MSS (size of TCP data “segment” in bytes) to path MTU.
I run pacman -Syu
about once a week on my Arch Linux
machines, to stay up-to-date,
avoid security problems and generally stay at the bleeding edge
of software revisions.
Today, I ran pacman -Syu
on my Dell R530 server
and it updated the PPP package.
Trouble ensued.
I used to try to do one dumb/weird hardware thing every year. One year, I used a Palm Pilot as a serial terminal for a Sun SPARCStation-10. Multiple serial cable adapters and gender changers involved.
My dumb hardware stunt for October 2024: 10 USB WiFi adapters on the same laptop.
I bought a TP-Link powerline ethernet starter kit.
After a reboot of my new server, the Kea DHCP server did not respond to DHCPDISCOVERs or DHCPREQUESTs
After I upgraded my WRT3200ACM router to OpenWRT v23.05.3, my laptop took minutes to get an IPv4 address when connected to my WRT3200ACM router’s WiFi. It only takes seconds to get an IPv4 address when connected to my other WiFi.
I ended up downgrading OpenWRT on the WRT3200ACM, but first I did a lot of work trying to track down the problem.
After I upgraded to OpenWRT 23.05.3, my Linksys WRT3200ACM WiFi router seems to interact poorly with my Dell E7470 laptop. It takes many tens of seconds for that laptop to acquire an IPv4 address via DHCP.
I decided to downgrade OpenWRT Linux on the router from 23.05.3 to 19.07.10. I believe it was running 19.07 before I started on my sysadmin journey of switching to a new server.
I decided to try the kea DHCP daemon on my production server.