921 reputation
312
bio website serverfault.com/users/148325/…
location St. Petersburg, Russia
age 24
visits member for 1 year, 10 months
seen Apr 19 at 5:51

I'm a systems administrator in a hosting company.


Mar
5
awarded  Critic
Mar
5
awarded  Custodian
Mar
5
comment Centos server crash
Please add some details: you hardware configuration, what software are you running.
Mar
5
comment Tomato dnsmasq - limit queries to specific name server
It SHOULD answer Internet requests as well, but it is your right to use it for resolving only several domains while using "server B" for other requests.
Mar
4
answered Tomato dnsmasq - limit queries to specific name server
Mar
4
comment Tomato dnsmasq - limit queries to specific name server
Are you querying PTR records?
Mar
3
answered How is it possible for the Root Name Servers to handle all DNS requests?
Mar
2
answered Error: after default apache port change
Mar
1
comment After changing SMTP port from 25 to 587 I can send, but now I don't receive emails
You should be root or run sudo tcpdump -nnn -i ethX port 25. And do not forget to replace ethX with actual name of your WAN interface, e.g. eth0 or eth1 or anything-you-have.
Mar
1
comment How to prioritize openvpn traffic?
I had exactly opposite situation. I used to establish openvpn connections through TCP and latency was extremely high. When I switched it to UDP it became fine.
Mar
1
comment After changing SMTP port from 25 to 587 I can send, but now I don't receive emails
Probably, outer SMTP servers or relays merely don't know how to connect to your SMTP server. Maybe they try to connect to port 25. You can clear it out by issuing tcpdump -nnn -i ethX port 25. Then try to send e-mail to your domain from another ISP. If there will be any output, then I'm right.
Feb
28
awarded  Analytical
Feb
28
awarded  Informed
Feb
28
awarded  Supporter
Feb
28
answered how can I view all of the machine/host names on a network
Feb
27
answered What does my ISP mean when they say they will provide “4 static IPs out of which 2 are usable”?
Feb
27
comment iptables config works in one Centos 6 server but not another one
I thing you may want to iptables -Z INPUT then tcpdump -i ethX port 22 on CentOS 6.0 box (don't forget to replace ethX with actual iface name). Then try to connect via ssh. You should see packets coming in on tcpdump output. And take a look at counters with iptables -n -L -v. Thus you can see if packets come in and which rule is applying to SSH connections.
Feb
27
answered linux vnc - continue to run programs while not logged in
Feb
26
comment ssh: Connection refused when access remotely
There is at least one router (192.168.50.1) between the work station and server. So, besides your server's iptables rules, it could be other rules on routers which could drop your packets. You could try tcpdump -i ethX port 22 on your server and try to ssh to it from work station to see if any packets goes in (don't forget to replace ethX with actual name of the world-looking iface). However, without complete understaning of your network topology, it's hard to tell.
Feb
26
comment ssh: Connection refused when access remotely
Show me please traceroute 192.168.1.123 from your work station. BTW, what OS are you running on the work station?