05-21-2019 11:19 PM
Hi,
I'm pretty new to business-level routers (I have programming and certain Ubuntu system admin experience though) but I'm facing a problem with Cisco 4431 router.
We have a client with quite strict security policy. The router resides in client's network, with external IP (12.34.56.78) assigned by client's network. The router manages a few Ubuntu servers (X, Y, Z, etc).
From my computer at my home, I can log into client's VPN and then access the router with ssh command, like
>ssh admin@12.34.56.78
or access server X with command like
>ssh -p 2210 guest@12.34.56.78
When I ssh into X, I issue command
>wget https://www.gnu.org/software/wget # I have wget installed actually, just to test internet connection
I got error like
>wget: unable to resolve host address: 'ftp.gnu.org'
I think I've set the networking files like "interfaces" correctly on server X and believe it's the client's firewall setting. However, the client's IT department says they don't block anything.
To avoid the possibility that I didn't configure X correctly, I also ssh into the router, and I issue command
#show ip nat trans
Pro Inside global Inside local Outside local Outside global
icmp 172.24.62.135:1 192.168.2.10:15172 8.8.8.8:15172 8.8.8.8:1
.......
tcp 172.24.62.135:2210 192.168.2.10:22 10.132.63.11:43853 10.132.63.11:43853
udp 172.24.62.135:1064 192.168.2.11:21803 129.176.199.5:53 129.176.199.5:53
Total number of translations: 114
I think this says the router is able to sending out outbound requests. However I wonder if there's any command that can show the router is sending outbound to www.gnu.org or www.google.com, but is blocked by the network. An imagined command like this:
#send_outbound_request_to_google
sending request out; sent; returned message saying you are blocked
I don't know much about router commands. Can you please help? TIA
-tx
Solved! Go to Solution.
05-23-2019 11:11 AM - edited 05-23-2019 11:12 AM
Hello,
what if you configure a local DNS entry ?
ip host ftp.gnu.org 209.51.188.20
05-23-2019 09:45 PM
05-23-2019 10:36 PM
The issue turns out to be a DNS issue (most likely or I think so). Basically, I can ping 72.30.35.9 (Yahoo IP) but not www.yahoo.com. Please refer to the link above for the progress. I guess it's better to have different post as the nature of the problem changed.
05-24-2019 01:55 AM
if the nature of the problem in related to this was one working - so suggest to close this thread rather we lay the issue all over.
so people can follow other thread and suggest what we can best based in your inputs.
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