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Entry  Fri Aug 6 13:13:28 2021, Anchal, Update, BHD, c1teststand subnetwork now accessible remotely 
    Reply  Mon Aug 9 10:38:48 2021, Anchal, Update, BHD, c1teststand subnetwork now accessible remotely 
Message ID: 16271     Entry time: Fri Aug 6 13:13:28 2021     Reply to this: 16273
Author: Anchal 
Type: Update 
Category: BHD 
Subject: c1teststand subnetwork now accessible remotely 

c1teststand subnetwork is now accessible remotely. To log into this network, one needs to do following:

  • Log into nodus or pianosa. (This will only work from these two computers)
  • ssh -CY controls@192.168.113.245
  • Password is our usual workstation password.
  • This will log you into c1teststand network.
  • From here, you can log into fb1, chiara, c1bhd and c1sus2  which are all part of the teststand subnetwork.

Just to document the IT work I did, doing this connection was bit non-trivial than usual.

  • The martian subnetwork is created by a NAT router which connects only nodus to outside GC network and all computers within the network have ip addresses 192.168.113.xxx with subnet mask of 255.255.255.0.
  • The cloned test stand network was also running on the same IP address scheme, mostly because fb1 and chiara are clones in this network. So every computer in this network also had ip addresses 192.168.113.xxx.
  • I setup a NAT router to connect to martian network forwarding ssh requests to c1teststand computer. My NAT router creates a separate subnet with IP addresses 10.0.1.xxx and suubnet mask 255.255.255.0 gated through 10.0.1.1.
  • However, the issue is for c1teststand, there are now two networks accessible which have same IP addresses 192.168.113.xxx. So when you try to do ssh, it always search in its local c1teststand subnetwork instead of routing through the NAT router to the martian network.
  • To work around this, I had to manually provide an ip router to c1teststand for connecting to two of the computers (nodus and pianosa) in martian network. This is done by:
    ip route add 192.168.113.200 via 10.0.1.1 dev eno1
    ip route add 192.168.113.216 via 10.0.1.1 dev eno1
  • This gives c1teststand specific path for ssh requests to/from these computers in the martian network.
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