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" ? 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 > -- Alain Spineux aspineux gmail com May the sources be with you