# ssh and nfs session freezes [solved]

## stegerpl

Hi,

frankly I don't know what I've done but suddently my ssh connection between two gentoo computers starts to freeze when I want to show more information.

The connection ist stable (   ssh root@computer2   ) and I can give commands with short outputs, but when I give a     cat /etc/fstab     or something similar, the connection freezes.

The same happens when I mount a nfs-share, I can change through the directories but when I give a  cat  it freezes again.

There is nothing in the logs of both computers. The problem was not there for the last three weeks during installation of computer2.

Any hints what's the reason for this strange behaviour? What should I post for you?

Peter

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## Hu

How are the computers connected?  What is the MTU between them?

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## stegerpl

It's a LAN network with CAT5 cables:  Computer 1  <==>  Netgear GBit Switch  GS105  <==>  Computer 2

On this Switch there is a third computer connected.

the /etc/conf.d/net  are:

Computer1:

```
# Konfiguration des Netzwerkzuganges

#

# eth0 => Internet

# eth1 => LAN

#

# Variante alles mit statischen Adressen - ist deutlich schneller beim Booten

#

config_eth0=( "192.168.1.3/24")

routes_eth0=( "default via 192.168.1.1" )

mtu_eth0="1420"

config_eth1=( "192.168.140.8/24" )

routes_eth1=( "192.168.140.0 via 192.168.140.8" )

mtu_eth1="6000"
```

Computer2:

```
config_eth0=( "192.168.140.6/24" )

routes_eth0=( "default via 192.168.140.8" )

dns_servers_eth0=( "195.96.0.4"  "195.70.224.45" "213.90.38.3" )

mtu_eth0="6000"
```

On Computer1 side there is a D-Link System Inc DGE-530T Gigabit Ethernet Adapter (skge => eht1) on an ASUS M3N78-EM (MCP77 Ethernet => forcedth => eth0)

On Computer2 side there is the Realtek 8111E Gigabit LAN onboard ASUS M4A88TD-M/USB3 (r8169 => eth0)

On Computer3 side there is also a D-Link System Inc DGE-530T Gigabit Ethernet Adapter on an ASUS A7N8X-VM/400 also connected to the Gigabit Switch

By the way today the connection works again   :Shocked:   -  is it possible, that the bandwidth of the Switch is to low to handle all three computers with mtu 6000 ?

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## Bircoph

Try to lower MTU on gigabit link. If you use iptables, check that icmp type 3 messages are not blocked. Try to tcpdump your traffic as well.

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## stegerpl

I tacked it down - it was a too high MTU but not for the computers but for the Switch - turning this device on/off resolved the issue.

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