Date: Mon, 24 Jun 1996 12:14:07 -0400 From: Luoqi Chen <luoqi@watermarkgroup.com> To: hackers@freebsd.org Subject: UDP still uses old address after pppd reconnects Message-ID: <31CEBECE.2D13@watermarkgroup.com>
next in thread | raw e-mail | index | archive | help
This morning I reconnected to my ISP at a different IP address using
pppd. And now at office I couldn't connect to one of my own udp server.
Initially, I thought my ISP screwed up. But after a little more research,
I believe this might be a bug with FreeBSD.
Last night my IP address was ppp-2.ts-1.ptn.idt.net, this morning I connected at
ppp-4.ts-1.ptn.idt.net. I wrote a little program sending UDP packet to its UDP
echo port from office and watched the traffic through tcpdump,
here is what I got,
% tcpdump -l -i ppp0 port echo
tcpdump: listening on ppp0
11:30:30.607374 lor.watermarkgroup.com.1751 > ppp-4.ts-1.ptn.idt.net.echo: udp 8
11:30:30.607674 ppp-2.ts-1.ptn.idt.net.echo > lor.watermarkgroup.com.1751: udp 8
This is only a problem for udp. I have no problem with tcp, tcp echo
correctly sends back using ppp-4 address, and I can telnet to it just fine.
By the way, I restarted inetd, it didn't help.
I checked ifconfig, it showed correct address,
% ifconfig ppp0
ppp0: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1500
inet 169.132.64.4 --> 169.132.64.253 netmask 0xffffff00
One reason that might cause this behavior is that I setup an ipip tunnel
between my machine at home and office. (Well, my ISP idt.net is not responding
to my complaint that I can't connect to ftp.freebsd.org since I signed up. And
I have to live with it before I find another cheap alternative. On the other
hand, my company has a more decent connection through PSI net. This in fact
has worked pretty well, until now). On my home PC, I setup a process listening
to the /dev/tun. It wraps up all ip packets in udp and sends over to a sun
at my office, where the packets are relay to the internet gateway throught
/dev/nit. Incoming packets are picked up by the sun using arp proxy and
sent back to my pc at home. This was done last Friday. I had not seen this
problem prior to that. I restarted the tunnel process after I reestablished my
ppp conntection, but it was not working now because of this udp problem.
Anyone have any idea?
-lq
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?31CEBECE.2D13>