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I have been trying to set up Debian Jessie on an old Dell Inspiron 300m. Right now the problem I have is, the ethernet connection only works partially.

  • ICMP works. I can ping IPs and FQDNs.
  • UDP works. I can get an IP via DHCP, and an FQDN from my home DNS server.
  • TCP does not work. I cannot open TCP connections to any service anywhere, and netstat's list of TCP connections is utterly empty - no local client ports, no loopback stuff, nothing at all.

iptables does not have anything beyond the normal UFW block-unsolicited-inbound stuff. This happens with both the onboard NIC and a USB-to-ethernet dongle I bought. The onboard is a Broadcom Tigon3, and for firmware for it is installed; I'm not sure what the dongle is, but it works on every Linux 3.x host I've tried it on.

Also, the kernel is the typical Jessie linux-image-586 package; not 686-pae, because the laptop has a Pentium M. I don't think that should make a difference, but who knows.

Update: It seems like this is a problem not with TCP, but with HTTP(S). I can connect out to servers on TCP ports, but there are no responses to HTTP requests. I've therefore updated the title.

The issue is still limited to only one computer (the old Inspiron).

  • Can you please post the output of sysctl -a | grep tcp? – MariusMatutiae Dec 30 '14 at 23:15
  • Here: pastebin.com/a2DHSjVd – DanL4096 Dec 30 '14 at 23:33
  • Can you connect to localhost? E.g., nc -l -p 1234 and then nc 127.0.0.1 1234. – derobert Dec 31 '14 at 0:01
  • BTW: My first guess (by far!) is that you actually have a firewall rule that is messing things up. My second guess would be (if it only applies to remote, not local, connections) something with TCP offload on the Ethernet card. My third guess is that you've done something crazy, e.g., compile a kernel w/o TCP support (not sure that's even possible). Do you get any error messages, either from the program trying to listen/connect or in dmesg? – derobert Dec 31 '14 at 13:17
  • Firewall rules are, as I said, all default for UFW. The kernel is the default one. I'll see if I can connect to localhost when I get home... – DanL4096 Dec 31 '14 at 15:05

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