hardware:shimtunnel
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hardware:shimtunnel [2019/01/10 15:06] – [Using a Shim Tunnel to send Netflow to a remote Trisul probe] veera | hardware:shimtunnel [2019/01/11 18:16] (current) – veera | ||
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- | A Shim tunnel encapsulates netflow payload inside a new UDP session by inserting a shim header ahead of the netflow header. This is an alternative method when you cannot deploy | + | A Shim tunnel encapsulates netflow payload inside a new UDP session by inserting a shim header ahead of the netflow header |
- | |||
- | The goal is for the Routers to send Netflow to the Gateway node, when will then forward it to the remote Trisul probe. | ||
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* Gateway Node real IP : 192.169.2.81 (both should be able to ping each other) | * Gateway Node real IP : 192.169.2.81 (both should be able to ping each other) | ||
* Port used : UDP 5111 | * Port used : UDP 5111 | ||
+ | * Source IP to use on the gateway end of shim tunnel : 10.251.52.4 | ||
+ | |||
+ | <note warning> | ||
+ | **Pre-check** | ||
+ | * ensure IP Forwarding is disabled '' | ||
+ | * local iptables firewall rules allow the UDP port '' | ||
+ | </ | ||
===== Download the Shim software ===== | ===== Download the Shim software ===== | ||
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Visit https:// | Visit https:// | ||
- | |||
- | Example | ||
< | < | ||
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- | Example | + | ==== Example |
< | < | ||
chmod +x nfshim.el7 | chmod +x nfshim.el7 | ||
./ | ./ | ||
+ | </ | ||
+ | |||
+ | |||
+ | ==== Example 2 : bind to a specific local address for tunnel endpoint ==== | ||
+ | |||
+ | < | ||
+ | chmod +x nfshim.el7 | ||
+ | ./ | ||
</ | </ | ||
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Restart | Restart | ||
+ | |||
+ | |||
+ | ===== Extra reference : Use Source NAT ===== | ||
+ | |||
+ | In the very unlikely scenario the above steps dont work and the desired source IP is not seen on the outgoing packets, use SNAT (Source NAT).This example NATs the source IP for udp packets to 5111 (custom netflow) | ||
+ | |||
+ | < | ||
+ | iptables -t nat -A | ||
+ | -o enp7s0 | ||
+ | </ | ||
+ | |||
+ | ==== To view rules ==== | ||
+ | |||
+ | < | ||
+ | iptables -t nat -L -v --line-numbers | ||
+ | </ | ||
+ | |||
+ | ==== To delete a rule with id 3 ==== | ||
+ | |||
+ | < | ||
+ | iptables -t nat -D POSTROUTING | ||
+ | </ | ||
hardware/shimtunnel.1547112984.txt.gz · Last modified: 2019/01/10 15:06 by veera