Date: Sun, 21 Jul 1996 03:11:50 -0500 (CDT) From: Kent Hamilton <kenth@HNS.St-Louis.Mo.US> To: pius@iago.ienet.com (Pius Fischer) Cc: freebsd-hackers@FreeBSD.ORG, terryl@ienet.com Subject: Re: bizarre network problem Message-ID: <199607210811.DAA06206@gwydion.hns.st-louis.mo.us> In-Reply-To: <199607120113.SAA25317@iago.ienet.com> from "Pius Fischer" at Jul 11, 96 06:13:33 pm
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Just FYI I'm seeing the exact same problem on one of my machines at work. The box is a P100 2.1-STABLE, with two Intel EtherExpress Pro 100B cards, on fxp0 and fpx1. > > We've been experiencing a strange network problem with a machine > running FreeBSD 2.1-stable. Any help would be greatly appreciated. > > Here's out setup: > > ---------------------- > | portia.ienet.com | ---------------------- ------------------- > | Pentium 166 MHz |----|3Com LinkSwitch 1000|--|gate.ienet.com |--> UUNet > | FreeBSD 2.1-STABLE | ---------------------- |Cisco 2500 series| > ---------------------- ------------------- > > So, we've got a Cisco connecting us to the Internet via a T-1. The > Cisco connects to our Ethernet hub (the LinkSwitch) via 10 Mb/s Ethernet > and the LinkSwitch connects to the host portia via 100 Mb/s Ethernet. > > We've also got a few other hosts connected to the LinkSwitch. > > The problem is that every once in a while packets coming from the outside > (coming in through our Cisco) don't make it to portia. This happens usually > whenever there is little network traffic to portia for a period of time. > traceroutes from the outside will get to the Cisco but not to portia. > > We put the Cisco into debugging mode (with 'debug ip packet') and it > appears to correctly forward the packets to portia, but a tcpdump process > running on portia never showed us any of those packets. > > This problem never occurs with packets sent from any of the other hosts > connected to the Ethernet hub. In fact, if I ping or telnet to portia from > one of these local hosts, portia appears to magically wake up and process > all packets correctly. > > And if I'm on portia's console and do an 'arp -a', normally I get a quick > response and see the arp cache. However, if this problem is happening, then > doing an 'arp -a' takes about 3 or 4 seconds before showing me the cache > and, again, portia wakes up and all packets are received and replied to. > > It appears that at the time the problem is happening, the arp cache entry > for the Cisco is incomplete, but that is probably just because it expired > and so shouldn't portia just reissue an arp query? Well, I guess it wouldn't > if it's not receiving anything to prompt the query. > > So the question is, is this a problem with the kernel or with our LinkSwitch > or with something else? What does 'arp -a' do that could cause the kernel to > wake up? It never fails to receive local packets like RIP updates every 30 > seconds and broadcast ARP queries, etc., but those, unlike the ping or telnet > don't cause it to wake up to remote traffic. > > portia uses an Intel EtherExpress PRO/100 LAN Adapter and the fxp0 device > driver. > > Any ideas? > > Thanks, > Pius > -- Kent Hamilton Play: KentH@HNS.St-Louis.MO.US NIC Handle: KH91 URL: http://www.icon-stl.net/~khamilto/ Blessed Be.... Work: KHamilton@Hunter.COM
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