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2021-08-09 14:19:19 +0000 received badge  Popular Question (source)
2020-07-02 07:19:23 +0000 marked best answer very low TCP RTOs

Hi there, i'm new to the wireshark community and looking for some help.

Since a few weeks, users in my company are complaining about slow SSH connections to linux servers. They work from a distant network ( MPLS or VPN). The whole infrastructure (servers & switching) is in a datacenter, carried by some Nexus 5000 and Nexus 2000 with multiples Vlans. The routing is managed by an old fortigate F1240B, which has not been updated since v5.0

After capturing some traffic, I see that I get a huge amount of TCP retransmission, and not only for SSH connections. Looking deep into the tcp frames, I see that the initial RTO is between 1 and 5 µS which looks very low.

Are such RTO normal ? If no, what can cause this and how can I solve this problem ?

Any help would be appreciated. I searched hours on the web but could find any answers..

As I understand, RTOs are defined by TCP and not applications or OS ?

2020-07-02 07:19:23 +0000 received badge  Scholar (source)
2020-03-26 09:25:01 +0000 commented answer very low TCP RTOs

Thanks for you explanations, its clear for me now ;)

2020-03-24 13:11:23 +0000 commented answer very low TCP RTOs

Yeah, I'm talking about retransmission timeouts. I understand that there are no retransmissions in my capture but duplic

2020-03-24 12:35:43 +0000 edited answer very low TCP RTOs

I did the capture directly from the firewall, and converted it to pcap file. This is maybe the reason of duplicates, as

2020-03-24 12:34:14 +0000 received badge  Rapid Responder
2020-03-24 12:34:14 +0000 answered a question very low TCP RTOs

I did the capture directly from the firewall, and converted it to pcap file. This is maybe the reason of duplicates, as

2020-03-24 08:18:38 +0000 received badge  Rapid Responder
2020-03-24 08:18:38 +0000 answered a question very low TCP RTOs

Please find the capture here : http://dl.free.fr/getfile.pl?file=/kR75KpTy

2020-03-23 18:02:21 +0000 received badge  Editor (source)
2020-03-23 18:02:21 +0000 edited question very low TCP RTOs

very low TCP RTOs Hi there, i'm new to the wireshark community and looking for some help. Since a few weeks, users in m

2020-03-23 17:54:17 +0000 asked a question very low TCP RTOs

very low TCP RTOs Hi there, i'm new to the wireshark community and looking for some help. Since a few weeks, users in m