On Wednesday 31 October 2007, Alain Spineux wrote: > Did you tried to ping other host inside and outside your network, your > gateway ? If not working, did you tried to arping your gateway ? > Did you look for packet with "tcpdump -n -i eth0" ? > I can successfully traceroute from the server to google. I didn't try an arping. I'll review the tcpdump messages today and let you know... Shawn > On 10/31/07, Shawn Everett <shawn at tandac.com> wrote: > > Hi Guys, > > > > I'm 100% sure this is not a Linux issue but I want a second opinion... > > > > I have a Linux server running CentOS. It was been absolutely perfect > > without any errors or problems. > > > > Since Monday it has been unable to send email. It is configured to > > act as a smart host. All email gets forwarded to smtp.isp.net. > > > > The server is on a network behind a firewall completely nat'd. No > > ports are forwarded to it. > > > > telnet smtp.isp.net 25 generates the following: > > Trying a.b.c.d... > > Connected to smtp.isp.net. > > Escape character is '^]'. > > > > And then nothing. All other machines can connect to smtp.isp.net 25 > > without a problem. They also use that host for their outgong mail > > server. > > > > Using links to surf the web has a similar result. It just hangs > > > > traceroute and nslookups work correctly. > > > > There are no errors anywhere. > > > > The network in question has various routing and vlan configurations, > > proxy servers and such. I tend to suspect they're the problem. > > They're also not in my control. > > > > The firewall does show the Linux box attempting to make SMTP > > connections but nothing else. > > > > Any ideas or suggestions would be appreciated. I have not yet > > rebooted the server. > > > > Shawn > > _______________________________________________ > > CentOS mailing list > > CentOS at centos.org > > http://lists.centos.org/mailman/listinfo/centos