athena@alessia.dei.unipd.it (Matteo Frigo) (10/11/90)
I have an Olivetti LSX3020 with Ethernet card, 8Mb ram and 280MB hard disk. I am on Internet. I have this problem: I can connect to Europe from here (Padova, Italy) and and to East Coast (NY and Boston), but I cannot have any tcp service from Berkeley, ucsd and so on. Next to the LSX I have a Sun 3 which works and has no problem in telnetting and ftp-ing to the entire world. I suspect it is a problem of timeouts, but I have absolutely no idea of where to put my hands on. I noted the machine worked before the new link between CNUCE and SURA, and in some moments it works again for a few minutes. Any help would be appreciated. I am quite disperate because the LSX acts as nameserver and mail exchanger for the domain dei.unipd.it, as other machines cannot be used for that for technical and administrative reasons, and my system has stopped working with no apparent reason. Matteo Frigo athena@alessia.dei.unipd.it ( try to reply with athena%alessia.dei.unipd.it@mcsun.eu.net because of these problems)
athena@alessia.dei.unipd.it (Matteo Frigo) (10/16/90)
[ I reply to myself :-) ] I have been able to solve the problem, and as it is a bug of of X/OS 2.2 I post the solution . The problem was in the incorrect TTL (time to live of tcp packets) which was set to 15, while the sun had 30. The constant TCP_TTL is defined in netinet/tcp_timer.h. My kernel was compiled with this low value, which inhibits tcp connections which far hosts. As I have not access to Olivetti kernel's sources, I made a patch directly on /usr/mixos/kernel/tcpip/libtcp_ip.a, using as guide the tcp sources from BSD4.3 . The constant is used in two object modules. I believe this is a problem of all LSX machines with X/OS 2.2 and I can give details on patching the kernel to anyone who is interested in. I would also thank all the people who gave me suggestions after my news. Matteo Frigo athena@alessia.dei.unipd.it (it works now !)