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VSAT technology and installation >> Gilat VSAT Forum >> MTU Problem on HUB
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Message started by mahrus on Oct 8th, 2009 at 11:28am

Title: MTU Problem on HUB
Post by mahrus on Oct 8th, 2009 at 11:28am
Does anyone having experience with MTU problem on HUB, i have VPN using FO connected to HUB and then to VSAT.
when i traceroute from the HQ to the VSAT , MTU is occured. below is my traceroute :

root@yaris:/> traceroute 10.171.36.224
trying to get source for 10.171.36.224
source should be 192.168.12.55
traceroute to 10.171.36.224 (10.171.36.224) from 192.168.12.55
(192.168.12.55), 30 hops max
outgoing MTU = 1500
1  10.24.32.11 (10.24.32.11)  2 ms  1 ms  1 ms
2  10.24.1.30 (10.24.1.30)  2 ms  2 ms  2 ms
3  10.12.1.30 (10.12.1.30)  2 ms  2 ms  2 ms
4  10.8.1.1 (10.8.1.1)  2 ms  2 ms  2 ms
5  10.130.5.1 (10.130.5.1)  5 ms  5 ms  5 ms
6  192.168.152.6 (192.168.152.6)  8 ms  7 ms  8 ms
7  172.24.31.101 (172.24.31.101)  9 ms  9 ms  9 ms
8  172.24.31.101 (172.24.31.101)  9 ms
fragmentation required, trying new MTU = 1492
8   9 ms
fragmentation required, trying new MTU = 1480
8   9 ms
fragmentation required, trying new MTU = 1472
8   9 ms
fragmentation required, trying new MTU = 1006
8  10.200.88.141 (10.200.88.141)  1254 ms  580 ms  576 ms
9  10.171.36.224 (10.171.36.224)  567 ms  564 ms  1238 ms

any answer will be helpfull... :)

Regard,
mahrus

Title: Re: MTU Problem on HUB
Post by Maxim Usatov on Oct 8th, 2009 at 4:13pm
Most probably your VPN is set up wrong. Do clients have automatic MTU discovery? Because VPN introduces some protocol overhead you have to make sure the outgoing packets, combined with the VPN overhead, would not exceed the maximum MTU the network can handle.

Sorry I can't advise anything particular as I don't know particulars about your setup.

Title: Re: MTU Problem on HUB
Post by mahrus on Oct 9th, 2009 at 9:47am
okay ill check the configuration of the VPN since it handle by different division i have to confirm to get the config.
meanwhile ill check the problem toward... ill traceroute from the VSAT to the HQ and will see does MTU problem also occured on this one.

thanks for ur quick reply :)

Regard
mahrus

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