connection issues

[Richard Riley]

Unless you have a serious firewall between this server and the internet, I'd be VERY leery about NOT using iptables to control traffic.  You could be exposing more than you want to those nasty hackers out there.

Richard 

 

> >-----Original Message-----
> >From: redhat-sysadmin-list-bounces at redhat.com 
> >[mailto:redhat-sysadmin-list-bounces at redhat.com] On Behalf 
> >Of Oluwagbenga Shobowale
> >Sent: Friday, June 20, 2008 3:09 PM
> >To: redhat-sysadmin-list at redhat.com
> >Subject: RE: connection issues
> >
> >Thanks..in fact I thought I stopped iptable, but in was 
> >iptable6 I stopped in services and I assumed it was iptable. 
> >Thanks.. its fine now...
> >
> >From: redhat-sysadmin-list-bounces at redhat.com
> >[mailto:redhat-sysadmin-list-bounces at redhat.com] On Behalf 
> >Of Alder, Stephen
> >(GTS)
> >Sent: Friday, June 20, 2008 7:35 PM
> >To: redhat-sysadmin-list at redhat.com
> >Subject: RE: connection issues
> >
> >Have you upgraded the kernel lately?
> >I've seen an upgraded kernel (big jumps in arch) make 
> >changes to /etc/sysctl.conf - where the ip forwarding kernel 
> >parameter is hardcoded.
> > 
> >Unlikely but easy enough to check and cross off as a possibility.
> >cat /etc/sysctl.conf | grep ip_forward
> > 
> >Steve
> > 
> >From: redhat-sysadmin-list-bounces at redhat.com
> >[mailto:redhat-sysadmin-list-bounces at redhat.com] On Behalf 
> >Of Oluwagbenga Shobowale
> >Sent: Friday, June 20, 2008 2:00 PM
> >To: redhat-sysadmin-list at redhat.com
> >Subject: connection issues
> > 
> >Hi,
> >Can anyone help me with this issue? I have a redhat box that 
> > connects to the internet, hence it acts as a router. This 
> >server runs sendmail, squid, pop3, samba etc..and all worked 
> >well at least before now.
> >However, recently it just stop working... When I logon 
> >locally to the machine I can surf the internet, however 
> >other computers linux or windows can't connect to any of its 
> >services. However, I can ping and it responds back...
> >For example, on the server, I run an nslookup on any domain 
> >it get resolved, however it does not work from any of the 
> >clients connected to it. I stop iptables to test ..still it 
> >does not work. I ran tcpdump on port 53 and I see traffic 
> >going in but the server does not respond with the answer. 
> >Same goes for ssh and other services. At the end I get the 
> >amount of filters passed and zero for the kernel. Hence I 
> >think traffic is getting into the kernel but its not passing 
> >it back out.
> > 
> >Can someone help with this problem? Should I do a fresh installation?
> >Thanks
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