Hi, Dan. On 17/01/16 18:33, Dan Ritter wrote: >> That is, it seems that the communication notebook <---> router works >> well regardless of the type of negotiation on the notebook side. >> >> But when I reconnect the firewall to the router, I lose again the link, >> regardless of whether on the firewall is enabled or not the >> auto-negotiation. > I'm afraid at this point my suggestions all involve hardware: > > - replace the TP-Link nic with something else, preferably with a > different chipset. Intel has been very reliable. > > - put a small ethernet switch (4 and 5 port switches are reasonably > cheap) between the router and firewall. > > - replace the router with something else. Well, after some time, I have returned to this matter. I have done one more test that I think is is conclusive. As I said, this Debian GNU/Linux firewall PC has two network cards: * eth0: RealTek RTL8139 (to the ADSL router) * eth1: VIA Rhine II (to the local network) The problem was with the RTL8139 card connected to the router. This only worked when setting up it to 10 Mbps. The VIA card connected to the switch of the local network never gave problems. So I now exchanged the configuration of the cards. Now the eth0 Realtek card connects to the internal network. It runs smoothly at 100 Mbps, full duplex and auto negotiation. So I think it was not a problem with the Realtek card. In fact, now the VIA card (that previously worked properly connected to the internal network switch) only works against ADSL router when it is set to 10 Mbps. All this makes me think the problem is in the ethernet interface of the ADSL router. I have requested a new router to Telefonica. I hope they send me a good one. This Zyxel router worked smoothly for quite some time. I also hope it have a default password to access the router and make the necessary settings (such as SNMP monitoring). Thanks for your reply. Kind regards, Daniel
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