I will start off by professing that I know next to nothing about Linux. However, we have a Linux server that has been installed. It is running CentOS. The problem is this: We have four subnets on our network (xxx.xxx.80.xxx, xxx.xxx.81.xxx, xxx.xxx.82.xxx, xxx.xxx.83.xxx). The server is on subnet 80 and the only Windows computers that can see or ping it are those on subnet 80. Noone else can ping it by name or ip. I asked the admin to check which DNS servers he is using and they are the correct ones that everyone else has mapped in their DHCP scope. If anyone has an idea about what may be causing this I would appreciate their input. Thank you.
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Need Some Help With Linux
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elgrandeperro
Technical User
Check the default route: netstat -rn
then check the netmask : /sbin/ifconfig -a (I am RHEL)
Ask your network guy what the netmask and route should be.
then check the netmask : /sbin/ifconfig -a (I am RHEL)
Ask your network guy what the netmask and route should be.
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The netmask should be 255.255.0.0 or /16
Just my 2¢
-Cole's Law: Shredded cabbage
--Greg
elgrandeperro
Technical User
uhhh,no.
The most likely guess would be 255.255.255.0 or /24,
but it could be a higher range without prior knowledge.
The most likely guess would be 255.255.255.0 or /24,
but it could be a higher range without prior knowledge.
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- #7
Thanks to all of your responses. We were finally able to get a resolution late yesterday. This server is administered by someone in a remote office. I had emailed them asking to check the defult route and the mask, explaining to verify that the mask is 255.255.252.0. Late yesterday afternoon the remote admin called me back saying that the mask was different but that he had changed it to 255.255.252.0. We are now able to ping this server from any workstation in our building. Thanks again for all your assistance.
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- #8
A subnet of /24 would be xxx.xxx.80.??? where ??? is 1 - 254
But that wouldn't see xxx.xxx.81 as on the same subnet.
A subnet of /16 would allow xxx.xxx.???.???, which *would* allow 80 to see 82, etc.
They essentially have 4 class C's that they're using. Easies to netmask it as a class B (although if I remember right, you may be able to do something like 255.255.239.0... but I'd have to think about it, and I don't think that 80 is in the right spot to do it that way... like I said, I'd have to do the math.)
--Greg (Now with 29 years of computer experience!)
Just my 2¢
-Cole's Law: Shredded cabbage
--Greg
- Moderator
- #9
Ahhh... yes... 80 is a common multiple, so you could actually use a subnet of 255.255.240.0, which would give you 4 networks, 80,81,82,83
But it's easier to do it as a class "B". lol
Just my 2¢
-Cole's Law: Shredded cabbage
--Greg
But it's easier to do it as a class "B". lol
Just my 2¢
-Cole's Law: Shredded cabbage
--Greg
elgrandeperro
Technical User
Yes, as long as 80, 81, 82 and 83 created a distinct subnet, the possibilities are varied (actually in either direction from /24!), because the net part could actually be part of the last byte like 255.255.255.240 (done this for home VPN). So only the network dude would know.
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