So i finally pulled myself together and formatted my server (4 years since last time i did a full reinstallation)

usually i just upgrade the kernel, but hey, time for some cleanup!

i save the .config file for the running kernel, as lazy i am, no need to spend more time than necessary.

since i decided to make it my router, i had to compile iptables support. which i did, and compiled rest of the netfilter/iptables related stuff as modules. so the weird thing was, while i were trying out an old iptables rules script

i got an error like

iptables -t nat -A POSTROUTING -o ppp0 -j MASQUERADE

FATAL: Module ip_tables not found.

iptables v1.3.8: can’t initialize iptables table `nat’: Table does not exist (do you need to insmod?)
Perhaps iptables or your kernel needs to be upgraded.

First i reinstalled iptables which made no difference, then the kernel again (included a few useless modules)

and i still got the error.

anyway, it seems like it can be rather unhealthy to use your current kernel config everytime you compile a new kernel, since there are some options which arent updated(no questions asked)

anyway, i did a make menuconfig, removed the support for networking (Networking – [*]Networking Support)

save the config file, opened it again, and enabled the support. all the original settings were removed, and i had to config it from scratch, but to my big surprise, i suddenly had alot more options to play with. and after compiling the kernel, rebooting – the problem was fixed